v0.101.2 build tags

Previously, build tags were not propagated from `holos render platform
-t validate` through to the underlying `holos render component` command.
This is a problem because validators need to be selectively enabled as a
work around until we have an audit mode field.

This patch fixes the problem by propagating command line tags from the
render platform command to the underlying commands.  This patch also
propagates tags for the show command.

.cspell.json

@@ -309,6 +309,7 @@
     "traefik",
     "transactionhistory",
     "tsdb",
+    "txtar",
     "typemeta",
     "udev",
     "uibutton",

.github/ISSUE_TEMPLATE/bug-report.md

@@ -0,0 +1,131 @@
+---
+name: Bug report
+about: Create a report to help us improve
+title: ''
+labels: NeedsInvestigation, Triage
+assignees: ''
+---
+
+<!--
+Please answer these questions before submitting your issue. Thanks!
+To ask questions, see https://github.com/holos-run/holos/discussions
+-->
+
+### What version of holos are you using (`holos --version`)?
+
+```
+0.0.0
+```
+
+### Does this issue reproduce with the latest release?
+
+<!--
+Get the latest release with:
+
+    brew install holos-run/tap/holos
+
+Or see https://holos.run/docs/v1alpha5/tutorial/setup/
+-->
+
+### What did you do?
+
+<!--
+Please provide a testscript that should pass, but does not because of the bug.
+See the below example.
+
+You can create a txtar from a directory with:
+
+  holos txtar ./path/to/dir
+
+Refer to: https://github.com/rogpeppe/go-internal/tree/master/cmd/testscript
+-->
+
+Steps to reproduce:
+
+```shell
+testscript -v -continue <<EOF
+```
+
+```txtar
+# Have: an error related to the imported Kustomize schemas.
+# Want: holos show buildplans to work.
+exec holos --version
+exec holos init platform v1alpha5 --force
+# remove the fix to trigger the bug
+rm cue.mod/pkg/sigs.k8s.io/kustomize/api/types/var.cue
+# want a BuildPlan shown
+exec holos show buildplans
+cmp stdout buildplan.yaml
+# want this error to go away
+! stderr 'cannot convert non-concrete value string'
+-- buildplan.yaml --
+kind: BuildPlan
+-- platform/example.cue --
+package holos
+
+Platform: Components: example: {
+	name: "example"
+	path: "components/example"
+}
+-- components/example/example.cue --
+package holos
+
+import "encoding/yaml"
+
+holos: Component.BuildPlan
+
+Component: #Kustomize & {
+	KustomizeConfig: Kustomization: patches: [
+		{
+			target: kind: "CustomResourceDefinition"
+			patch: yaml.Marshal([{
+				op:    "add"
+				path:  "/metadata/annotations/example"
+				value: "example-value"
+			}])
+		},
+	]
+}
+```
+```shell
+EOF
+```
+
+### What did you expect to see?
+
+The testscript should pass.
+
+### What did you see instead?
+
+The testscript fails because of the bug.
+
+```txt
+# Have: an error related to the imported Kustomize schemas.
+# Want: holos show buildplans to work. (0.168s)
+> exec holos --version
+[stdout]
+0.100.1-2-g9b10e23-dirty
+> exec holos init platform v1alpha5 --force
+# remove the fix to trigger the bug (0.000s)
+> rm cue.mod/pkg/sigs.k8s.io/kustomize/api/types/var.cue
+# want a BuildPlan shown (0.091s)
+> exec holos show buildplans
+[stderr]
+could not run: holos.spec.artifacts.0.transformers.0.kustomize.kustomization.patches.0.target.name: cannot convert non-concrete value string at builder/v1alpha5/builder.go:218
+holos.spec.artifacts.0.transformers.0.kustomize.kustomization.patches.0.target.name: cannot convert non-concrete value string:
+    $WORK/cue.mod/gen/sigs.k8s.io/kustomize/api/types/var_go_gen.cue:33:2
+[exit status 1]
+FAIL: <stdin>:8: unexpected command failure
+> cmp stdout buildplan.yaml
+diff stdout buildplan.yaml
+--- stdout
++++ buildplan.yaml
+@@ -0,0 +1,1 @@
++kind: BuildPlan
+
+FAIL: <stdin>:9: stdout and buildplan.yaml differ
+# want this error to go away (0.000s)
+> ! stderr 'cannot convert non-concrete value string'
+FAIL: <stdin>:11: unexpected match for `cannot convert non-concrete value string` found in stderr: cannot convert non-concrete value string
+failed run
+```

.github/workflows/dev-deploy.yaml

@@ -2,7 +2,7 @@ name: Dev Deploy
 
 on:
   push:
-    branches: ['main', 'dev-deploy']
+    branches: ['dev-deploy']
 
 jobs:
   deploy:

README.md

@@ -1,35 +1,130 @@
-## Holos - A Holistic Development Platform
+# Holos
 
 <img width="50%"
 align="right"
 style="display: block; margin: 40px auto;"
 src="https://openinfrastructure.co/blog/2016/02/27/logo/logorectangle.png">
 
-Building and maintaining a software development platform is a complex and time
-consuming endeavour.  Organizations often dedicate a team of 3-4 who need 6-12
-months to build the platform.
+[Holos] is a configuration management tool for Kubernetes implementing the
+[rendered manifests pattern]. It handles configurations ranging from single
+resources to multi-cluster platforms across regions.
 
-Holos is a tool and a reference platform to reduce the complexity and speed up
-the process of building a modern, cloud native software development platform.
+Key components:
+- Platform schemas defining component integration
+- Building blocks unifying Helm, Kustomize and Kubernetes configs with CUE
+- BuildPlan pipeline for generating, transforming and validating manifests
 
-- **Accelerate new projects** - Reduce time to market and operational complexity by starting your new project on top of the Holos reference platform.
-- **Modernize existing projects** - Incrementally incorporate your existing platform services into Holos for simpler integration.
-- **Unified configuration model** - Increase safety and reduce the risk of config changes with CUE.
-- **First class Helm and Kustomize support** - Leverage and reuse your existing investment in existing configuration tools such as Helm and Kustomize.
-- **Modern Authentication and Authorization** - Holos seamlessly integrates platform identity and access management with zero-trust beyond corp style authorization policy.
+```mermaid
+---
+title: Rendering Overview
+---
+graph LR
+    Platform[<a href="https://holos.run/docs/v1alpha5/api/author/#Platform">Platform</a>]
+    Component[<a href="https://holos.run/docs/v1alpha5/api/author/#ComponentConfig">Components</a>]
 
-## Quick Installation
+    Helm[<a href="https://holos.run/docs/v1alpha5/api/author/#Helm">Helm</a>]
+    Kustomize[<a href="https://holos.run/docs/v1alpha5/api/author/#Kustomize">Kustomize</a>]
+    Kubernetes[<a href="https://holos.run/docs/v1alpha5/api/author/#Kubernetes">Kubernetes</a>]
 
-```console
-go install github.com/holos-run/holos/cmd/holos@latest
+    BuildPlan[<a href="https://holos.run/docs/v1alpha5/api/core/#BuildPlan">BuildPlan</a>]
+
+    ResourcesArtifact[<a href="https://holos.run/docs/v1alpha5/api/core/#Artifact">Resources<br/>Artifact</a>]
+    GitOpsArtifact[<a href="https://holos.run/docs/v1alpha5/api/core/#Artifact">GitOps<br/>Artifact</a>]
+
+    Generators[<a href="https://holos.run/docs/v1alpha5/api/core/#Generator">Generators</a>]
+    Transformers[<a href="https://holos.run/docs/v1alpha5/api/core/#Transformer">Transformers</a>]
+    Validators[<a href="https://holos.run/docs/v1alpha5/api/core/#Validator">Validators</a>]
+    Files[Manifest<br/>Files]
+
+    Platform --> Component
+    Component --> Helm --> BuildPlan
+    Component --> Kubernetes --> BuildPlan
+    Component --> Kustomize --> BuildPlan
+
+    BuildPlan --> ResourcesArtifact --> Generators
+    BuildPlan --> GitOpsArtifact --> Generators
+
+    Generators --> Transformers --> Validators --> Files
 ```
 
-## Docs and Support
+## Setup
 
-The documentation for developing and using Holos is available at: https://holos.run
+```shell
+brew install holos-run/tap/holos
+```
 
-For discussion and support, [open a discussion](https://github.com/orgs/holos-run/discussions/new/choose).
+Refer to [setup] for other installation methods and dependencies.
+
+## Example
+
+See our [tutorial] for a complete hello world example.
+
+```cue showLineNumbers
+package holos
+
+holos: Component.BuildPlan
+
+Component: #Helm & {
+	Name: "podinfo"
+	Chart: {
+		version: "6.6.2"
+		repository: {
+			name: "podinfo"
+			url:  "https://stefanprodan.github.io/podinfo"
+		}
+	}
+	Values: ui: {
+		message: string | *"Hello World" @tag(message, type=string)
+	}
+}
+```
+
+## Organizational Role
+
+Platform engineers use Holos to generate Kubernetes manifests, both locally and
+in CI pipelines. The manifests are committed to version control and deployed via
+GitOps tools like ArgoCD or Flux.
+
+Holos integrates seamlessly with existing Helm charts, Kustomize bases, and
+other version-controlled configurations.
+
+## Advantages of Holos
+
+### Safe
+
+Holos leverages [CUE] for strong typing and validation of configuration data,
+ensuring consistent output from Helm and other tools.
+
+### Consistent
+
+A unified pipeline processes all configurations - whether from CUE, Helm, or
+Kustomize - through the same well-defined stages.
+
+### Flexible
+
+Composable building blocks for generation, transformation, validation and
+integration let teams assemble workflows that match their needs.
+
+The core is intentionally unopinionated about platform configuration patterns.
+Common needs like environments and clusters are provided as customizable
+[topics] recipes rather than enforced structures.
+
+## Getting Help
+
+Get support through our [Discord] channel or [GitHub discussions]. Configuration
+challenges arise at all experience levels - we welcome your questions and are
+here to help.
 
 ## License
 
 Holos is licensed under Apache 2.0 as found in the [LICENSE file](LICENSE).
+
+[Holos]: https://holos.run
+[rendered manifests pattern]: https://akuity.io/blog/the-rendered-manifests-pattern
+[CUE]: https://cuelang.org/
+[Discord]: https://discord.gg/JgDVbNpye7
+[GitHub discussions]: https://github.com/holos-run/holos/discussions
+[Why CUE for Configuration]: https://holos.run/blog/why-cue-for-configuration/
+[topics]: https://holos.run/docs/topics/
+[setup]: https://holos.run/docs/setup/
+[tutorial]: https://holos.run/docs/tutorial/

api/author/v1alpha5/definitions.go

@@ -65,8 +65,10 @@ type ComponentConfig struct {
 
 	// Resources represents kubernetes resources mixed into the rendered manifest.
 	Resources core.Resources
-	// KustomizeConfig represents the configuration kustomize.
+	// KustomizeConfig represents the kustomize configuration.
 	KustomizeConfig KustomizeConfig
+	// Validators represent checks that must pass for output to be written.
+	Validators map[NameLabel]core.Validator
 	// Artifacts represents additional artifacts to mix in.  Useful for adding
 	// GitOps resources.  Each Artifact is unified without modification into the
 	// BuildPlan.

api/core/v1alpha5/types.go

@@ -40,14 +40,6 @@ type BuildPlanSpec struct {
 	Disabled bool `json:"disabled,omitempty" yaml:"disabled,omitempty"`
 }
 
-// BuildPlanSource reflects the origin of a [BuildPlan].  Useful to save a build
-// plan to a file, then re-generate it without needing to process a [Platform]
-// component collection.
-type BuildPlanSource struct {
-	// Component reflects the component that produced the build plan.
-	Component Component `json:"component,omitempty" yaml:"component,omitempty"`
-}
-
 // Artifact represents one fully rendered manifest produced by a [Transformer]
 // sequence, which transforms a [Generator] collection.  A [BuildPlan] produces
 // an [Artifact] collection.
@@ -72,6 +64,7 @@ type Artifact struct {
 	Artifact     FilePath      `json:"artifact,omitempty" yaml:"artifact,omitempty"`
 	Generators   []Generator   `json:"generators,omitempty" yaml:"generators,omitempty"`
 	Transformers []Transformer `json:"transformers,omitempty" yaml:"transformers,omitempty"`
+	Validators   []Validator   `json:"validators,omitempty" yaml:"validators,omitempty"`
 	Skip         bool          `json:"skip,omitempty" yaml:"skip,omitempty"`
 }
 
@@ -206,15 +199,37 @@ type Kustomize struct {
 // is expected to happen in CUE against the kubectl version the user prefers.
 type Kustomization map[string]any
 
-// FileContent represents file contents.
-type FileContent string
-
 // FileContentMap represents a mapping of file paths to file contents.
 type FileContentMap map[FilePath]FileContent
 
 // FilePath represents a file path.
 type FilePath string
 
+// FileContent represents file contents.
+type FileContent string
+
+// Validator validates files.  Useful to validate an [Artifact] prior to writing
+// it out to the final destination.  Holos may execute validators concurrently.
+// See the [validators] tutorial for an end to end example.
+//
+// [validators]: https://holos.run/docs/v1alpha5/tutorial/validators/
+type Validator struct {
+	// Kind represents the kind of transformer. Must be Kustomize, or Join.
+	Kind string `json:"kind" yaml:"kind" cue:"\"Command\""`
+	// Inputs represents the files to validate.  Usually the final Artifact.
+	Inputs []FilePath `json:"inputs" yaml:"inputs"`
+	// Command represents a validation command.  Ignored unless kind is Command.
+	Command Command `json:"command,omitempty" yaml:"command,omitempty"`
+}
+
+// Command represents a command vetting one or more artifacts.  Holos appends
+// fully qualified input file paths to the end of the args list, then executes
+// the command.  Inputs are written into a temporary directory prior to
+// executing the command and removed afterwards.
+type Command struct {
+	Args []string `json:"args,omitempty" yaml:"args,omitempty"`
+}
+
 // InternalLabel is an arbitrary unique identifier internal to holos itself.
 // The holos cli is expected to never write a InternalLabel value to rendered
 // output files, therefore use a InternalLabel when the identifier must be

cmd/holos/tests/cli/cue-vet.txt

@@ -0,0 +1,12 @@
+# https://github.com/holos-run/holos/issues/358
+# holos cue vet should fail verifications with exit code 1
+! exec holos cue vet ./policy --path strings.ToLower(kind) ./data/secret.yaml
+# holos cue vet should report validation errors to stderr
+stderr 'Forbidden. Use an ExternalSecret instead.'
+
+-- data/secret.yaml --
+kind: Secret
+-- policy/validators.cue --
+package policy
+
+secret: kind: "Forbidden. Use an ExternalSecret instead."

cmd/holos/tests/v1alpha5/guides/helm.txt

@@ -7,11 +7,11 @@ cd $WORK
 exec holos generate platform v1alpha5 --force
 
 # Platforms are empty by default.
-exec holos render platform ./platform
+exec holos render platform
 stderr -count=1 '^rendered platform'
 
 # Holos uses CUE to build a platform specification.
-exec cue export --expression holos --out=yaml ./platform
+exec holos show platform
 cmp stdout want/1.platform_spec.yaml
 
 # Define the host and port in projects/blackbox.schema.cue
@@ -22,7 +22,7 @@ mv projects/platform/components/prometheus/prometheus.cue.disabled projects/plat
 mv platform/prometheus.cue.disabled platform/prometheus.cue
 
 # Render the platform to render the prometheus chart.
-exec holos render platform ./platform
+exec holos render platform
 stderr -count=1 '^rendered prometheus'
 stderr -count=1 '^rendered platform'
 cmp deploy/components/prometheus/prometheus.gen.yaml want/1.prometheus.gen.yaml
@@ -73,8 +73,8 @@ core.#BuildPlan & {
 	metadata: name: _Tags.component.name
 }
 -- want/1.platform_spec.yaml --
-kind: Platform
 apiVersion: v1alpha5
+kind: Platform
 metadata:
   name: default
 spec:

cmd/holos/tests/v1alpha5/issues/holos-show.txt

@@ -106,9 +106,6 @@ spec:
             kustomization:
               apiVersion: kustomize.config.k8s.io/v1beta1
               kind: Kustomization
-              labels:
-                - includeSelectors: false
-                  pairs: {}
               resources:
                 - resources.gen.yaml
 ---
@@ -135,9 +132,6 @@ spec:
             kustomization:
               apiVersion: kustomize.config.k8s.io/v1beta1
               kind: Kustomization
-              labels:
-                - includeSelectors: false
-                  pairs: {}
               resources:
                 - resources.gen.yaml
 ---
@@ -164,9 +158,6 @@ spec:
             kustomization:
               apiVersion: kustomize.config.k8s.io/v1beta1
               kind: Kustomization
-              labels:
-                - includeSelectors: false
-                  pairs: {}
               resources:
                 - resources.gen.yaml
 ---
@@ -193,9 +184,6 @@ spec:
             kustomization:
               apiVersion: kustomize.config.k8s.io/v1beta1
               kind: Kustomization
-              labels:
-                - includeSelectors: false
-                  pairs: {}
               resources:
                 - resources.gen.yaml
 -- want/buildplans.1.yaml --
@@ -222,9 +210,6 @@ spec:
             kustomization:
               apiVersion: kustomize.config.k8s.io/v1beta1
               kind: Kustomization
-              labels:
-                - includeSelectors: false
-                  pairs: {}
               resources:
                 - resources.gen.yaml
 -- want/buildplans.2.yaml --
@@ -251,9 +236,6 @@ spec:
             kustomization:
               apiVersion: kustomize.config.k8s.io/v1beta1
               kind: Kustomization
-              labels:
-                - includeSelectors: false
-                  pairs: {}
               resources:
                 - resources.gen.yaml
 -- want/buildplans.3.yaml --
@@ -280,9 +262,6 @@ spec:
             kustomization:
               apiVersion: kustomize.config.k8s.io/v1beta1
               kind: Kustomization
-              labels:
-                - includeSelectors: false
-                  pairs: {}
               resources:
                 - resources.gen.yaml
 ---
@@ -309,9 +288,6 @@ spec:
             kustomization:
               apiVersion: kustomize.config.k8s.io/v1beta1
               kind: Kustomization
-              labels:
-                - includeSelectors: false
-                  pairs: {}
               resources:
                 - resources.gen.yaml
 ---
@@ -338,9 +314,6 @@ spec:
             kustomization:
               apiVersion: kustomize.config.k8s.io/v1beta1
               kind: Kustomization
-              labels:
-                - includeSelectors: false
-                  pairs: {}
               resources:
                 - resources.gen.yaml
 -- want/buildplans.4.yaml --
@@ -367,9 +340,6 @@ spec:
             kustomization:
               apiVersion: kustomize.config.k8s.io/v1beta1
               kind: Kustomization
-              labels:
-                - includeSelectors: false
-                  pairs: {}
               resources:
                 - resources.gen.yaml
 ---
@@ -396,9 +366,6 @@ spec:
             kustomization:
               apiVersion: kustomize.config.k8s.io/v1beta1
               kind: Kustomization
-              labels:
-                - includeSelectors: false
-                  pairs: {}
               resources:
                 - resources.gen.yaml
 ---
@@ -425,9 +392,6 @@ spec:
             kustomization:
               apiVersion: kustomize.config.k8s.io/v1beta1
               kind: Kustomization
-              labels:
-                - includeSelectors: false
-                  pairs: {}
               resources:
                 - resources.gen.yaml
 ---
@@ -454,8 +418,5 @@ spec:
             kustomization:
               apiVersion: kustomize.config.k8s.io/v1beta1
               kind: Kustomization
-              labels:
-                - includeSelectors: false
-                  pairs: {}
               resources:
                 - resources.gen.yaml

cmd/holos/tests/v1alpha5/issues/issue348-kustomize-patch-name.txt

@@ -0,0 +1,64 @@
+# https://github.com/holos-run/holos/issues/348
+# when the optional kustomize patch name field is omitted
+exec holos init platform v1alpha5 --force
+# want a buildplan shown
+exec holos show buildplans
+cmp stdout buildplan.yaml
+# want this error to go away
+! stderr 'cannot convert non-concrete value string'
+-- platform/example.cue --
+package holos
+
+Platform: Components: example: {
+	name: "example"
+	path: "components/example"
+}
+-- components/example/example.cue --
+package holos
+
+import "encoding/yaml"
+
+holos: Component.BuildPlan
+
+Component: #Kustomize & {
+	KustomizeConfig: Kustomization: patches: [
+		{
+			target: kind: "CustomResourceDefinition"
+			patch: yaml.Marshal([{
+				op:    "add"
+				path:  "/metadata/annotations/example"
+				value: "example-value"
+			}])
+		},
+	]
+}
+-- buildplan.yaml --
+kind: BuildPlan
+apiVersion: v1alpha5
+metadata:
+  name: example
+spec:
+  artifacts:
+    - artifact: components/example/example.gen.yaml
+      generators:
+        - kind: Resources
+          output: resources.gen.yaml
+      transformers:
+        - kind: Kustomize
+          inputs:
+            - resources.gen.yaml
+          output: components/example/example.gen.yaml
+          kustomize:
+            kustomization:
+              apiVersion: kustomize.config.k8s.io/v1beta1
+              kind: Kustomization
+              patches:
+                - patch: |
+                    - op: add
+                      path: /metadata/annotations/example
+                      value: example-value
+                  target:
+                    kind: CustomResourceDefinition
+                    name: ""
+              resources:
+                - resources.gen.yaml

cmd/holos/tests/v1alpha5/issues/issue366-cue-build-tags.txt

@@ -0,0 +1,50 @@
+# https://github.com/holos-run/holos/issues/366
+# Build tags conditionally include CUE files.
+env HOME=$WORK
+
+exec holos init platform v1alpha5 --force
+exec holos show platform
+cmp stdout want/empty.yaml
+
+exec holos show platform -t foo
+cmp stdout want/foo.yaml
+
+-- platform/empty.cue --
+@if(foo)
+package holos
+
+Platform: Components: foo: _
+-- platform/metadata.cue --
+package holos
+
+Platform: Components: [NAME=string]: {
+  name: NAME
+  path: "components/empty"
+  labels: "app.holos.run/name": NAME
+  annotations: "app.holos.run/description": "\(NAME) empty test case"
+}
+-- components/empty/empty.cue --
+package holos
+
+Component: #Kubernetes & {}
+holos: Component.BuildPlan
+-- want/empty.yaml --
+apiVersion: v1alpha5
+kind: Platform
+metadata:
+  name: default
+spec:
+  components: []
+-- want/foo.yaml --
+apiVersion: v1alpha5
+kind: Platform
+metadata:
+  name: default
+spec:
+  components:
+    - annotations:
+        app.holos.run/description: foo empty test case
+      labels:
+        app.holos.run/name: foo
+      name: foo
+      path: components/empty

cmd/holos/tests/v1alpha5/schemas/kubernetes.txt

@@ -31,6 +31,7 @@ spec:
         - kind: Resources
           output: resources.gen.yaml
           resources: {}
+      validators: []
       transformers:
         - kind: Kustomize
           inputs:
@@ -38,9 +39,6 @@ spec:
           output: components/no-name/no-name.gen.yaml
           kustomize:
             kustomization:
-              labels:
-                - includeSelectors: false
-                  pairs: {}
               resources:
                 - resources.gen.yaml
               kind: Kustomization

cmd/holos/tests/v1alpha5/schemas/validators.txt

@@ -0,0 +1,37 @@
+# https://github.com/holos-run/holos/issues/357
+exec holos init platform v1alpha5 --force
+! exec holos render platform
+stderr 'secret.kind: conflicting values "Forbidden. Use an ExternalSecret instead." and "Secret"'
+
+-- validators.cue --
+package holos
+
+import "github.com/holos-run/holos/api/author/v1alpha5:author"
+
+#ComponentConfig: author.#ComponentConfig & {
+	Validators: cue: {
+		kind: "Command"
+		command: args: ["holos", "cue", "vet", "./policy", "--path", "strings.ToLower(kind)"]
+	}
+}
+-- policy/validations.cue --
+package validations
+
+secret: kind: "Forbidden. Use an ExternalSecret instead."
+-- platform/example.cue --
+package holos
+
+Platform: Components: example: {
+	name: "example"
+	path: "components/example"
+}
+-- components/example/secret.cue --
+package holos
+
+holos: Component.BuildPlan
+
+Component: #Kubernetes & {
+	Resources: Secret: test: {
+		metadata: name: "test"
+	}
+}

doc/md/api/author.md

@@ -62,8 +62,10 @@ type ComponentConfig struct {
 
     // Resources represents kubernetes resources mixed into the rendered manifest.
     Resources core.Resources
-    // KustomizeConfig represents the configuration kustomize.
+    // KustomizeConfig represents the kustomize configuration.
     KustomizeConfig KustomizeConfig
+    // Validators represent checks that must pass for output to be written.
+    Validators map[NameLabel]core.Validator
     // Artifacts represents additional artifacts to mix in.  Useful for adding
     // GitOps resources.  Each Artifact is unified without modification into the
     // BuildPlan.

doc/md/api/core.md

@@ -16,9 +16,9 @@ Package core contains schemas for a [Platform](<#Platform>) and [BuildPlan](<#Bu
 
 - [type Artifact](<#Artifact>)
 - [type BuildPlan](<#BuildPlan>)
-- [type BuildPlanSource](<#BuildPlanSource>)
 - [type BuildPlanSpec](<#BuildPlanSpec>)
 - [type Chart](<#Chart>)
+- [type Command](<#Command>)
 - [type Component](<#Component>)
 - [type File](<#File>)
 - [type FileContent](<#FileContent>)
@@ -38,6 +38,7 @@ Package core contains schemas for a [Platform](<#Platform>) and [BuildPlan](<#Bu
 - [type Resource](<#Resource>)
 - [type Resources](<#Resources>)
 - [type Transformer](<#Transformer>)
+- [type Validator](<#Validator>)
 - [type Values](<#Values>)
 
 
@@ -59,6 +60,7 @@ type Artifact struct {
     Artifact     FilePath      `json:"artifact,omitempty" yaml:"artifact,omitempty"`
     Generators   []Generator   `json:"generators,omitempty" yaml:"generators,omitempty"`
     Transformers []Transformer `json:"transformers,omitempty" yaml:"transformers,omitempty"`
+    Validators   []Validator   `json:"validators,omitempty" yaml:"validators,omitempty"`
     Skip         bool          `json:"skip,omitempty" yaml:"skip,omitempty"`
 }
 ```
@@ -85,18 +87,6 @@ type BuildPlan struct {
 }
 ```
 
-<a name="BuildPlanSource"></a>
-## type BuildPlanSource {#BuildPlanSource}
-
-BuildPlanSource reflects the origin of a [BuildPlan](<#BuildPlan>). Useful to save a build plan to a file, then re\-generate it without needing to process a [Platform](<#Platform>) component collection.
-
-```go
-type BuildPlanSource struct {
-    // Component reflects the component that produced the build plan.
-    Component Component `json:"component,omitempty" yaml:"component,omitempty"`
-}
-```
-
 <a name="BuildPlanSpec"></a>
 ## type BuildPlanSpec {#BuildPlanSpec}
 
@@ -129,6 +119,17 @@ type Chart struct {
 }
 ```
 
+<a name="Command"></a>
+## type Command {#Command}
+
+Command represents a command vetting one or more artifacts. Holos appends fully qualified input file paths to the end of the args list, then executes the command. Inputs are written into a temporary directory prior to executing the command and removed afterwards.
+
+```go
+type Command struct {
+    Args []string `json:"args,omitempty" yaml:"args,omitempty"`
+}
+```
+
 <a name="Component"></a>
 ## type Component {#Component}
 
@@ -414,6 +415,22 @@ type Transformer struct {
 }
 ```
 
+<a name="Validator"></a>
+## type Validator {#Validator}
+
+Validator validates files. Useful to validate an [Artifact](<#Artifact>) prior to writing it out to the final destination. Holos may execute validators concurrently. See the [validators](<https://holos.run/docs/v1alpha5/tutorial/validators/>) tutorial for an end to end example.
+
+```go
+type Validator struct {
+    // Kind represents the kind of transformer. Must be Kustomize, or Join.
+    Kind string `json:"kind" yaml:"kind" cue:"\"Command\""`
+    // Inputs represents the files to validate.  Usually the final Artifact.
+    Inputs []FilePath `json:"inputs" yaml:"inputs"`
+    // Command represents a validation command.  Ignored unless kind is Command.
+    Command Command `json:"command,omitempty" yaml:"command,omitempty"`
+}
+```
+
 <a name="Values"></a>
 ## type Values {#Values}
 

doc/md/topics/component-parameters.mdx

@@ -1,12 +0,0 @@
----
-description: Re-use components by passing in parameters.
-slug: component-parameters
-sidebar_position: 400
----
-
-# Component Parameters
-
-Key points:
-
-1. Components can be reused.
-2. The Platform spec can pass user defined parameters to a component.

doc/md/topics/fleets.mdx

@@ -1,12 +0,0 @@
----
-description: Organize clusters into fleets.
-slug: fleets
-sidebar_position: 300
----
-
-# Fleets
-
-Key points:
-
-1. Workload fleet.
-2. Management fleet.

doc/md/topics/gitops/argocd-application.mdx

@@ -177,7 +177,7 @@ source:
 <Tabs groupId="E150C802-7162-4FBF-82A7-77D9ADAEE847">
   <TabItem value="command" label="Command">
 ```bash
-holos render platform ./platform
+holos render platform
 ```
   </TabItem>
   <TabItem value="output" label="Output">
@@ -218,7 +218,6 @@ spec:
 [CUE Module]: https://cuelang.org/docs/reference/modules/
 [CUE Tags]: https://cuelang.org/docs/howto/inject-value-into-evaluation-using-tag-attribute/
 [Application]: https://argo-cd.readthedocs.io/en/stable/user-guide/application-specification/
-[Component Parameters]: ../component-parameters.mdx
 [Platform]: ../../api/author.md#Platform
 [ComponentConfig]: ../../api/author.md#ComponentConfig
 [Artifact]: ../../api/core.md#Artifact

doc/md/topics/management-cluster.mdx

@@ -1,15 +0,0 @@
----
-description: Management Cluster
-slug: management-cluster
-sidebar_position: 200
----
-
-# Management Cluster
-
-Key points:
-
-1. Namespaces
-2. Certificates
-3. Secrets
-4. CronJobs
-5. GKE autopilot

doc/md/topics/secrets-management.mdx

@@ -1,12 +0,0 @@
----
-description: Secrets Management
-slug: secrets-management
-sidebar_position: 150
----
-
-# Secrets Management
-
-Key points:
-
-1. Namespaces
-2. ExternalSecrets

doc/md/topics/structures/clusters.mdx

@@ -39,11 +39,12 @@ mkdir holos-multiple-clusters && cd holos-multiple-clusters
 holos init platform v1alpha5
 ```
 
-### Example Component
+### Using an example Component
 
 <CommonComponent />
 
-We'll integrate the component with the platform after we define clusters.
+We'll integrate the component with the platform after we define the
+configuration structures.
 
 ## Defining Clusters
 
@@ -320,7 +321,7 @@ Render the platform to configure `podinfo` on each cluster.
 <Tabs groupId="34A2D80B-0E86-4142-B65B-7DF70C47E1D2">
   <TabItem value="command" label="Command">
 ```bash
-holos render platform ./platform
+holos render platform
 ```
   </TabItem>
   <TabItem value="output" label="Output">

doc/md/topics/structures/environments.mdx

@@ -7,23 +7,479 @@ sidebar_position: 130
 
 import Tabs from '@theme/Tabs';
 import TabItem from '@theme/TabItem';
+import CommonComponent from '../../common/example-component.mdx';
 
 # Environments
 
 ## Overview
 
+This topic covers how to model environments in Holos. We'll define schemas for
+`#Environment` and `#Environments` to represent one environment and a
+collection. The `Environments: #Environments` struct maps environment names to
+configurations.
+
+:::note
+This approach unifies the component definition with the overall platform
+configuration, creating a tight coupling between the two.
+:::
+
+This tight coupling is appropriate when you're configuring your own platform.
+For example:
+
+1. When you're integrating third party software into your own platform.
+2. When you're configuring first party in-house software into your own platform.
+
+This approach is not well suited to writing a component to share outside of your
+own organization, which we can think of as configuring someone else's platform.
+
 ## The Code
 
 ### Generating the structure
 
+Use `holos init platform` to generate a minimal platform structure:
+
+```shell
+mkdir holos-environments-tutorial && cd holos-environments-tutorial
+holos init platform v1alpha5
+```
+
 ### Using an example Component
 
+<CommonComponent />
+
+We'll integrate the component with the platform after we define the
+configuration structures.
+
 ## Defining Environments
 
-### Defining one Environment
+We'll define an `#Environment` schema `#Environments` collection.  We'll use
+these schemas to define an `Environments` struct of concrete configuration
+values.
 
-### Defining a collection of Environments
+### Assumptions
 
-## Rendering manifests
+There are two tiers of environments, prod and nonprod.  Prod environments
+organized along broad jurisdictions, for example US and EU.  Nonprod
+environments are organized by purpose, dev, test, and stage.
 
-## Reviewing the Manifests
+### Prototyping the data
+
+Before we define the schema, let's prototype the data structure we want to work
+with from the perspective of each component.
+
+Let's imagine we're configuring `podinfo` to comply with regulations.  When
+podinfo is deployed to production in the EU, we'll configure opt-in behavior.
+In the US we'll configure opt-out behavior.
+
+We'll pass the environment name as a component parameter.  The component
+definition can then look up the jurisdiction to determine the appropriate
+configuration values.
+
+```shell
+holos cue export --out=yaml --expression Environments
+```
+
+```yaml showLineNumbers
+prod-pdx:
+  name: prod-pdx
+  tier: prod
+  jurisdiction: us
+  state: oregon
+prod-cmh:
+  name: prod-cmh
+  tier: prod
+  jurisdiction: us
+  state: ohio
+prod-ams:
+  name: prod-ams
+  tier: prod
+  jurisdiction: eu
+  state: netherlands
+dev:
+  name: dev
+  tier: nonprod
+  jurisdiction: us
+  state: oregon
+test:
+  name: test
+  tier: nonprod
+  jurisdiction: us
+  state: oregon
+stage:
+  name: stage
+  tier: nonprod
+  jurisdiction: us
+  state: oregon
+```
+
+### Defining the schema
+
+Given the example structure, we can write a schema to define and validate the
+data.
+
+```shell
+cat <<EOF > environments.schema.cue
+```
+```cue showLineNumbers
+package holos
+
+#Environment: {
+	name:         string
+	tier:         "prod" | "nonprod"
+	jurisdiction: "us" | "eu" | "uk" | "global"
+	state:        "oregon" | "ohio" | "germany" | "netherlands" | "england" | "global"
+
+	// Prod environment names must be prefixed with prod for clarity.
+	if tier == "prod" {
+		name: "prod" | =~"^prod-"
+	}
+}
+
+#Environments: {
+	[NAME=string]: #Environment & {
+		name: NAME
+	}
+}
+```
+```shell
+EOF
+```
+
+### Adding configuration
+
+With a schema defined, we can fill in the concrete values.
+
+```shell
+cat <<EOF > environments.cue
+```
+```cue showLineNumbers
+package holos
+
+// Injected from Platform.spec.components.parameters.EnvironmentName
+EnvironmentName: string @tag(EnvironmentName)
+
+Environments: #Environments & {
+	"prod-pdx": {
+		tier:         "prod"
+		jurisdiction: "us"
+		state:        "oregon"
+	}
+	"prod-cmh": {
+		tier:         "prod"
+		jurisdiction: "us"
+		state:        "ohio"
+	}
+	"prod-ams": {
+		tier:         "prod"
+		jurisdiction: "eu"
+		state:        "netherlands"
+	}
+	// Nonprod environments are colocated together.
+	_nonprod: {
+		tier:         "nonprod"
+		jurisdiction: "us"
+		state:        "oregon"
+	}
+	dev:   _nonprod
+	test:  _nonprod
+	stage: _nonprod
+}
+```
+```shell
+EOF
+```
+
+### Inspecting the configuration
+
+Inspect the `Environments` data structure to verify the schema and concrete
+values are what we want.
+
+<Tabs groupId="FF820F5A-A85F-464D-B299-39CAAFFCE5C6">
+  <TabItem value="command" label="Command">
+```bash
+holos cue export --out=yaml --expression Environments
+```
+  </TabItem>
+  <TabItem value="output" label="Output">
+```yaml showLineNumbers
+prod-pdx:
+  name: prod-pdx
+  tier: prod
+  jurisdiction: us
+  state: oregon
+prod-cmh:
+  name: prod-cmh
+  tier: prod
+  jurisdiction: us
+  state: ohio
+prod-ams:
+  name: prod-ams
+  tier: prod
+  jurisdiction: eu
+  state: netherlands
+dev:
+  name: dev
+  tier: nonprod
+  jurisdiction: us
+  state: oregon
+test:
+  name: test
+  tier: nonprod
+  jurisdiction: us
+  state: oregon
+stage:
+  name: stage
+  tier: nonprod
+  jurisdiction: us
+  state: oregon
+```
+  </TabItem>
+</Tabs>
+
+This looks like our prototype, we're confident we can iterate over each
+environment and get a handle on the configuration values we need.
+
+## Integrating components
+
+The `Environments` data structure unlocks the capability to look up concrete
+values specific to a named environment.  We'll use this capability to configure
+the `podinfo` component in compliance with the regulations of the jurisdiction.
+
+### Configuring the environment
+
+Inject the environment name when we integrate `podinfo` with the platform.
+
+```shell
+cat <<EOF > platform/podinfo.cue
+```
+```cue showLineNumbers
+package holos
+
+Platform: Components: {
+	podinfoPDX: ProdPodinfo & {_city: "pdx"}
+	podinfoCMH: ProdPodinfo & {_city: "cmh"}
+	podinfoAMS: ProdPodinfo & {_city: "ams"}
+	podinfoDEV: {
+		name: "podinfo-dev"
+		path: "components/podinfo"
+		labels: "app.holos.run/component": "podinfo"
+		parameters: EnvironmentName:       "dev"
+	}
+}
+
+let ProdPodinfo = {
+	_city: string
+	name:  "podinfo-\(_city)"
+	path:  "components/podinfo"
+	labels: "app.holos.run/component": "podinfo"
+	labels: "app.holos.run/tier":      "prod"
+	labels: "app.holos.run/city":      _city
+	parameters: EnvironmentName:       "prod-\(_city)"
+}
+```
+
+### Using the environment
+
+Now we can configure `podinfo` based on the jurisdiction of the environment.
+
+```shell
+cat <<EOF > components/podinfo/cookie-consent.cue
+```
+```cue showLineNumbers
+package holos
+
+// Schema definition for our configuration.
+#Values: {
+	ui: enableCookieConsent: *true | false
+	ui: message:             string
+}
+
+// Map jurisdiction to helm values
+JurisdictionValues: {
+	// Enable cookie consent by default in any jurisdiction.
+	[_]: #Values
+	// Disable in the US.
+	us: ui: enableCookieConsent: false
+	eu: ui: enableCookieConsent: true
+}
+
+// Look up the configuration values associated with the environment name.
+Component: Values: JurisdictionValues[Environments[EnvironmentName].jurisdiction]
+```
+```shell
+EOF
+```
+
+### Inspecting the BuildPlans
+
+With the above configuration, we can inspect the buildplans for this component.
+The prod environment in Amsterdam has cookie consent enabled on line 26.
+
+<Tabs groupId="6EC991F3-F78C-43F1-8A6D-E68D8BDAF58B">
+  <TabItem value="command" label="Command">
+```bash
+holos show buildplans --selector app.holos.run/city=ams
+```
+  </TabItem>
+  <TabItem value="output" label="Output">
+```yaml showLineNumbers
+kind: BuildPlan
+apiVersion: v1alpha5
+metadata:
+  name: podinfo-ams
+  labels:
+    app.holos.run/city: ams
+    app.holos.run/component: podinfo
+    app.holos.run/name: podinfo-ams
+    app.holos.run/tier: prod
+spec:
+  artifacts:
+    - artifact: components/podinfo-ams/podinfo-ams.gen.yaml
+      generators:
+        - kind: Helm
+          output: helm.gen.yaml
+          helm:
+            chart:
+              name: podinfo
+              version: 6.6.2
+              release: podinfo
+              repository:
+                name: podinfo
+                url: https://stefanprodan.github.io/podinfo
+            values:
+              ui:
+                # highlight-next-line
+                enableCookieConsent: true
+                message: Hello World
+        - kind: Resources
+          output: resources.gen.yaml
+      transformers:
+        - kind: Kustomize
+          inputs:
+            - helm.gen.yaml
+            - resources.gen.yaml
+          output: components/podinfo-ams/podinfo-ams.gen.yaml
+          kustomize:
+            kustomization:
+              apiVersion: kustomize.config.k8s.io/v1beta1
+              kind: Kustomization
+              labels:
+                - includeSelectors: false
+                  pairs: {}
+              resources:
+                - helm.gen.yaml
+                - resources.gen.yaml
+    - artifact: gitops/podinfo-ams.application.gen.yaml
+      generators:
+        - kind: Resources
+          output: gitops/podinfo-ams.application.gen.yaml
+          resources:
+            Application:
+              podinfo-ams:
+                apiVersion: argoproj.io/v1alpha1
+                kind: Application
+                metadata:
+                  name: podinfo-ams
+                  namespace: argocd
+                spec:
+                  destination:
+                    server: https://kubernetes.default.svc
+                  project: default
+                  source:
+                    path: deploy/components/podinfo-ams
+                    repoURL: https://github.com/brenix/holos-demo.git
+                    targetRevision: main
+```
+  </TabItem>
+</Tabs>
+
+In Portland cookie consent is disabled.
+
+<Tabs groupId="3438335B-1FFC-4838-B8DE-C54B8346CDB4">
+  <TabItem value="command" label="Command">
+```bash
+holos show buildplans --selector app.holos.run/city=pdx
+```
+  </TabItem>
+  <TabItem value="output" label="Output">
+```yaml showLineNumbers
+kind: BuildPlan
+apiVersion: v1alpha5
+metadata:
+  name: podinfo-pdx
+  labels:
+    app.holos.run/city: pdx
+    app.holos.run/component: podinfo
+    app.holos.run/name: podinfo-pdx
+    app.holos.run/tier: prod
+spec:
+  artifacts:
+    - artifact: components/podinfo-pdx/podinfo-pdx.gen.yaml
+      generators:
+        - kind: Helm
+          output: helm.gen.yaml
+          helm:
+            chart:
+              name: podinfo
+              version: 6.6.2
+              release: podinfo
+              repository:
+                name: podinfo
+                url: https://stefanprodan.github.io/podinfo
+            values:
+              ui:
+                # highlight-next-line
+                enableCookieConsent: false
+                message: Hello World
+        - kind: Resources
+          output: resources.gen.yaml
+      transformers:
+        - kind: Kustomize
+          inputs:
+            - helm.gen.yaml
+            - resources.gen.yaml
+          output: components/podinfo-pdx/podinfo-pdx.gen.yaml
+          kustomize:
+            kustomization:
+              apiVersion: kustomize.config.k8s.io/v1beta1
+              kind: Kustomization
+              labels:
+                - includeSelectors: false
+                  pairs: {}
+              resources:
+                - helm.gen.yaml
+                - resources.gen.yaml
+    - artifact: gitops/podinfo-pdx.application.gen.yaml
+      generators:
+        - kind: Resources
+          output: gitops/podinfo-pdx.application.gen.yaml
+          resources:
+            Application:
+              podinfo-pdx:
+                apiVersion: argoproj.io/v1alpha1
+                kind: Application
+                metadata:
+                  name: podinfo-pdx
+                  namespace: argocd
+                spec:
+                  destination:
+                    server: https://kubernetes.default.svc
+                  project: default
+                  source:
+                    path: deploy/components/podinfo-pdx
+                    repoURL: https://github.com/brenix/holos-demo.git
+                    targetRevision: main
+```
+  </TabItem>
+</Tabs>
+
+## Concluding Remarks
+
+In this topic we covered how to use a CUE structure to define attributes of prod
+and nonprod environments.
+
+1. We passed the environment name as a parameter to each component using a CUE `@tag`.
+2. The component definition uses the environment name as a key to get a handle
+on attributes. For example, the jurisdiction a service operates within.
+3. The example podinfo component uses an additional structure to map
+jurisdictions to concrete configuration values.

doc/md/topics/structures/owners.mdx

@@ -1,29 +0,0 @@
----
-slug: owners
-title: Owners
-description: Managing and mapping projects to owners.
-sidebar_position: 150
----
-
-import Tabs from '@theme/Tabs';
-import TabItem from '@theme/TabItem';
-
-# Owners
-
-## Overview
-
-## The Code
-
-### Generating the structure
-
-### Using an example Component
-
-## Defining Owners
-
-### Defining one Owner
-
-### Defining a collection of Owners
-
-## Rendering manifests
-
-## Reviewing the Manifests

doc/md/topics/structures/projects.mdx

@@ -1,29 +0,0 @@
----
-slug: projects
-title: Projects
-description: Managing components organizing them into projects.
-sidebar_position: 140
----
-
-import Tabs from '@theme/Tabs';
-import TabItem from '@theme/TabItem';
-
-# Projects
-
-## Overview
-
-## The Code
-
-### Generating the structure
-
-### Using an example Component
-
-## Defining Projects
-
-### Defining one Project
-
-### Defining a collection of Projects
-
-## Rendering manifests
-
-## Reviewing the Manifests

doc/md/topics/workload-cluster.mdx

@@ -1,12 +0,0 @@
----
-description: Workload Cluster
-slug: workload-cluster
-sidebar_position: 250
----
-
-# Workload Cluster
-
-Key points:
-
-1. Namespaces
-2. ExternalSecrets

doc/md/tutorial/cue.mdx

@@ -12,34 +12,34 @@ import TabItem from '@theme/TabItem';
 
 ## Overview
 
-This tutorial demonstrates mixing additional resources into a component using
-CUE.  Holos components frequently mix in resources so we don't need to modify
-existing charts or manifests.  We'll add an [ExternalSecret] resource to the
-podinfo Helm chart we configured in the [Hello Holos] tutorial.
+This tutorial demonstrates how to add additional resources to a component using
+CUE. Holos components often mix in resources, eliminating the need to modify
+existing charts or manifests. In this tutorial, we'll add an [ExternalSecret]
+resource to the podinfo Helm chart configured in the [Hello Holos] tutorial.
 
 Key concepts:
 
 1. Resources are validated against `#Resources` defined at the root.
-2. Custom Resource Definitions need to be imported with timoni.
-3. Helm, Kustomize, and CUE can be mixed in together in the same component.
+2. Custom Resource Definitions need to be imported using Timoni.
+3. Helm, Kustomize, and CUE can be mixed together within the same component.
 
 ## The Code
 
-### Generating the structure
+### Generating the Structure
 
-Use `holos` to generate a minimal platform directory structure.  First, create
-and cd into a blank directory. Then use the `holos generate platform` command to
-generate a minimal platform.
+Use `holos` to generate a minimal platform directory structure. First, create
+and navigate into a blank directory. Then, use the `holos generate platform`
+command to generate a minimal platform.
 
 ```shell
 mkdir holos-cue-tutorial && cd holos-cue-tutorial
 holos init platform v1alpha5
 ```
 
-### Creating the component
+### Creating the Component
 
-Create the directory for the `podinfo` component.  Create an empty file and then
-add the following CUE configuration to it.
+Create the directory for the `podinfo` component. Create an empty file, then add
+the following CUE configuration to it.
 
 ```bash
 mkdir -p components/podinfo
@@ -72,7 +72,7 @@ Component: #Helm & {
 EOF
 ```
 
-Integrate the component with the platform.
+Register the component with the platform.
 
 ```bash
 cat <<EOF > platform/podinfo.cue
@@ -94,7 +94,7 @@ Render the platform.
 <Tabs groupId="tutorial-hello-render-manifests">
   <TabItem value="command" label="Command">
 ```bash
-holos render platform ./platform
+holos render platform
 ```
   </TabItem>
   <TabItem value="output" label="Output">
@@ -161,12 +161,13 @@ field validates against the `#Resources` definition in [resources.cue].
 
 ### Importing CRDs
 
-Holos includes CUE schema definitions of the ExternalSecret custom resource
-definition (CRD).  These schemas are located in the `cue.mod` directory, written by
-the `holos init platform` command we executed at the start of this tutorial.
+Holos includes CUE schema definitions for the ExternalSecret Custom Resource
+Definition (CRD). These schemas are located in the `cue.mod` directory,
+generated by the `holos init platform` command executed at the start of this
+tutorial.
 
-Import your own custom resource definitions using [timoni].  We imported the
-ExternalSecret CRDs embedded into `holos` with the following command.
+To import your own custom resource definitions, use [Timoni]. We imported the
+ExternalSecret CRDs embedded in `holos` using the following command.
 
 <Tabs groupId="35B1A1A1-D7DF-4D27-A575-28556E182096">
   <TabItem value="command" label="Command">
@@ -203,16 +204,16 @@ Take a look at
 the imported definitions.
 :::
 
-Once imported, the last step is to add the resource kind to the `#Resources`
-struct.  This is most often accomplished by adding a new file which cue unifies
-with the existing [resources.cue] file.
+Once imported, the final step is to add the resource kind to the `#Resources`
+struct. Typically, this is done by creating a new file that CUE unifies with the
+existing [resources.cue] file.
 
 ## Reviewing Changes
 
 Render the platform with the `ExternalSecret` mixed into the podinfo component.
 
 ```shell
-holos render platform ./platform
+holos render platform
 ```
 
 Take a look at the diff to see the mixed in `ExternalSecret`.
@@ -249,22 +250,20 @@ index 6e4aec0..f79e9d0 100644
 ```
 
 We saw how to mix in resources using the `Resources` field of the
-[ComponentConfig].  This technique approach works for every kind of component in
-Holos.  We did this without needing to fork the upstream Helm chart so we can
-easily update to new podinfo versions as they're released.
+[ComponentConfig]. This approach works for every kind of component in Holos,
+allowing seamless integration without needing to fork the upstream Helm chart.
+This way, we can easily update to new podinfo versions as they're released.
 
 ## Trying Locally
 
-Optionally apply the manifests Holos rendered to a [Local Cluster].
+Optionally, apply the manifests rendered by Holos to a [Local Cluster] for
+testing.
 
 ## Next Steps
 
 This tutorial uses the `#Resources` structure to map resource kinds to their
-schema definitions in CUE.  This structure is defined in `resources.cue` at the
-root of the tree.  Take a look at [resources.cue] to see this mapping structure.
-
-Continue to the next tutorial to learn how to define your own data structures
-similar to this `#Resources` structure.
+schema definitions in CUE. This structure is defined in `resources.cue` at the
+root of the tree. Take a look at [resources.cue] to see this mapping structure.
 
 [Local Cluster]: ../topics/local-cluster.mdx
 [ExternalSecret]: https://external-secrets.io/latest/api/externalsecret/

doc/md/tutorial/hello-holos.mdx

@@ -15,32 +15,22 @@ import ComponentSequence from '@site/src/diagrams/render-component-sequence.mdx'
 
 ## Overview
 
-One of the first exercises we do when learning a new programming language is
-printing out a "Hello World!" greeting. Hello Holos configures the [podinfo Helm
-chart][podinfo] producing a similar greeting from a Kubernetes Service.
+Like a traditional "Hello World" program, we'll start by configuring the
+[podinfo Helm chart][podinfo] to output a greeting from a Kubernetes Service.
+This introduces the core concept of wrapping Helm charts as Holos Components.
 
-By the end of this tutorial you have an understanding of how to wrap a Helm
-Chart as a Holos Component.
+## Implementation
 
-## The Code
+### Initialize Platform Structure
 
-### Generating the structure
-
-Use `holos` to generate a minimal platform directory structure.  Start by
-creating a blank directory to hold the platform configuration.
+Create and initialize a minimal platform:
 
 ```shell
 mkdir holos-tutorial && cd holos-tutorial
-```
-
-Use the `holos init platform` command to initialize a minimal platform in the
-blank directory.
-
-```shell
 holos init platform v1alpha5
 ```
 
-Here's the filesystem tree we'll build in this tutorial.
+The resulting directory structure:
 
 <Tabs groupId="80D04C6A-BC83-44D0-95CC-CE01B439B159">
 <TabItem value="tree" label="Tree">
@@ -104,10 +94,9 @@ initialization.
 </TabItem>
 </Tabs>
 
-### Creating a component
+### Create the Component
 
-Start by creating a directory for the `podinfo` component.  Create an empty file
-and then add the following CUE configuration to it.
+Configure the `podinfo` component:
 
 ```bash
 mkdir -p components/podinfo
@@ -145,20 +134,19 @@ EOF
 ```
 
 :::important
-CUE loads all of `*.cue` files in the component directory to define component,
-similar to Go packages.
+Like Go packages, CUE loads all `*.cue` files in the component directory to
+define the component.
 :::
 
 :::note
-CUE _also_ loads all `*.cue` files from the component leaf directory to the
-platform root directory.  In this example, `#Helm` on line 6 is defined in
-`schema.cue` at the root.
+CUE recursively loads `*.cue` files from the component directory up to the
+platform root. For example, `#Helm` referenced on line 6 is defined in
+root-level `schema.cue`.
 :::
 
-### Integrating the component
+### Add to Platform
 
-Integrate the `podinfo` component into the platform by creating a new CUE file
-in the `platform` directory with the following content.
+Register the `podinfo` component in `platform/podinfo.cue`:
 
 ```bash
 cat <<EOF > platform/podinfo.cue
@@ -178,19 +166,17 @@ EOF
 ```
 
 :::tip
-Component parameters may have any name as long as they don't start with
-`holos_`.
+Parameter names are unrestricted, except for the reserved `holos_` prefix.
 :::
 
-## Rendering manifests
+## Generate Manifests
 
-Render a manifest for `podinfo` using the `holos render platform ./platform`
-command.  The `platform/` directory is the main entrypoint for this command.
+Render the `podinfo` configuration:
 
 <Tabs groupId="E150C802-7162-4FBF-82A7-77D9ADAEE847">
   <TabItem value="command" label="Command">
 ```bash
-holos render platform ./platform
+holos render platform
 ```
   </TabItem>
   <TabItem value="output" label="Output">
@@ -202,10 +188,7 @@ rendered platform in 1.938759417s
   </TabItem>
 </Tabs>
 
-:::important
-Holos rendered the following manifest file by executing `helm template` after
-caching `podinfo` locally.
-:::
+Holos executes `helm template` with locally cached charts to generate:
 
 ```txt
 deploy/components/podinfo/podinfo.gen.yaml
@@ -348,21 +331,24 @@ grep -B2 Hello deploy/components/podinfo/podinfo.gen.yaml
 
 ## Breaking it down
 
-We run `holos render platform ./platform` because the CUE files in the platform
-directory export a [Platform] resource to `holos`.  The platform directory is
-the entrypoint to the platform rendering process.
+We run `holos render platform` because the CUE files in the platform directory
+export a [Platform] resource to `holos`.
 
-Components are the building blocks for a Platform.  The `platform/podinfo.cue`
-file integrates the `podinfo` Component with the Platform.
+:::important
+The `platform/` directory is the default entry point to the platform rendering
+process.  Override with `--platform <dir>`.
+:::
 
-Holos requires two fields to integrate a component with the platform.
+Components are the building blocks of a Platform. The `platform/podinfo.cue`
+file integrates the `podinfo` component with the Platform.
+
+Holos requires two fields to integrate a component with the platform:
 
 1. A unique name for the component.
-2. The component path to the directory containing the CUE files exporting a
+2. The component path to the directory containing the CUE files that export a
 `BuildPlan` defining the component.
 
-Component parameters are optional.  They allow re-use of the same component.
-Refer to the [Component Parameters] topic for more information.
+Component parameters are optional and allow re-use of the same component.
 
 <Tabs groupId="67C1EE71-3EA8-4568-9F6D-0072BA09FF12">
   <TabItem value="overview" label="Rendering Overview">
@@ -379,12 +365,12 @@ Refer to the [Component Parameters] topic for more information.
 
 ## Next Steps
 
-We've shown how to integrate one Helm chart to the Platform, but we haven't yet
-covered multiple Helm charts.  Continue on with the next tutorial to learn how
-Holos makes it easy to inject values into multiple components safely and easily.
+We've shown how to integrate one Helm chart into the Platform, but we haven't
+yet covered multiple Helm charts. Continue with the next tutorial to learn how
+Holos makes it easy to inject values into multiple components safely and
+efficiently.
 
 [podinfo]: https://github.com/stefanprodan/podinfo
 [CUE Module]: https://cuelang.org/docs/reference/modules/
 [CUE Tags]: https://cuelang.org/docs/howto/inject-value-into-evaluation-using-tag-attribute/
 [Platform]: ../api/author.md#Platform
-[Component Parameters]: ../topics/component-parameters.mdx

doc/md/tutorial/helm-values.mdx

@@ -17,28 +17,23 @@ import TabItem from '@theme/TabItem';
 
 ## Overview
 
-Holos makes it easier to integrate multiple Helm charts together.  Holos adds
-valuable capabilities to Helm and Kustomize.
+Holos simplifies integrating multiple Helm charts by adding valuable
+capabilities to Helm and Kustomize:
 
-1. Inject the same value into two or more charts to integrate them safer than Helm alone.
-2. Add strong type checking and validation of constraints for Helm input values.
-3. Implementation of the [rendered manifests pattern].
+1. Inject the same value into multiple charts more safely than using Helm alone.
+2. Add strong type checking and validation for Helm input values.
+3. Implement the [rendered manifests pattern].
 
-We'll manage the [prometheus] and [blackbox] Helm Charts in this tutorial.
-Unfortunately, the upstream `values.yaml` files are misconfigured by default.
-Prometheus tries to connect to Blackbox at the wrong host and port.
-
-:::tip
-Holos and CUE makes it easy to fix this problem by integrating them correctly.
-The integrated charts will stay in lock step over time.
-:::
+In this tutorial, we'll manage the [prometheus] and [blackbox] Helm charts. By
+default, the upstream `values.yaml` files are misconfigured, causing Prometheus
+to connect to Blackbox at the wrong host and port.
 
 ## The Code
 
 ### Generating the structure
 
-Use `holos` to generate a minimal platform directory structure.  First, create
-and cd into a blank directory. Then use the `holos init platform` command.
+Use `holos` to generate a minimal platform directory structure. First, create
+and navigate into a blank directory, then use the `holos init platform` command:
 
 ```shell
 mkdir holos-helm-values-tutorial
@@ -46,10 +41,10 @@ cd holos-helm-values-tutorial
 holos init platform v1alpha5
 ```
 
-Make a commit to track changes.
+Make an initial commit to track changes:
 
 ```bash
-git init . && git add . && git commit -m initial
+git init . && git add . && git commit -m "initial commit"
 ```
 
 ### Managing the Components
@@ -114,10 +109,9 @@ EOF
   </TabItem>
 </Tabs>
 
-### Integrating the Components
+### Register the Components
 
-Integrate the components with the platform by adding the following file to the
-platform directory.
+Register the components with the platform by adding the following file to the platform directory.
 
 ```bash
 cat <<EOF > platform/prometheus.cue
@@ -145,7 +139,7 @@ Render the platform.
 <Tabs groupId="33D6BFED-62D8-4A42-A26A-F3121D57C4E5">
   <TabItem value="command" label="Command">
 ```bash
-holos render platform ./platform
+holos render platform
 ```
   </TabItem>
   <TabItem value="output" label="Output">
@@ -182,9 +176,8 @@ git add . && git commit -m 'add blackbox and prometheus'
 
 ### Importing Helm Values
 
-Holos renders the helm charts with their default values.  We can import these
-default values into CUE so we can easily work with them as structured data
-instead of text markup.
+Holos renders Helm charts with their default values. We can import these default
+values into CUE to work with them as structured data instead of text markup.
 
 ```bash
 holos cue import \
@@ -206,15 +199,15 @@ These commands convert the YAML data into CUE code and nest the values under the
 `Values` field of the `Helm` struct.
 
 :::important
-CUE unifies `values.cue` with the other `*.cue` files in the same directory.
+CUE unifies `values.cue` with the other `\*.cue` files in the same directory.
 :::
 
-Render the platform and commit the results.
+Render the platform using `holos render platform` and commit the results.
 
 <Tabs groupId="BDDCD65A-2E9D-4BA6-AAE2-8099494D5E4B">
   <TabItem value="command" label="Command">
 ```bash
-holos render platform ./platform
+holos render platform
 ```
   </TabItem>
   <TabItem value="output" label="Output">
@@ -244,9 +237,10 @@ git add . && git commit -m 'import values'
 
 ### Managing Common Configuration
 
-Define a structure to hold the configuration values we want both helm charts to
-use.  We add this configuration to the `components` directory so it's in scope
-for all components.
+To manage shared configuration for both Helm charts, define a structure that
+holds the common configuration values. Place this configuration in the
+`components` directory to ensure it is accessible to all components.
+
 
 ```bash
 cat <<EOF > components/blackbox.cue
@@ -296,13 +290,13 @@ git add . && git commit -m 'add blackbox configuration'
   </TabItem>
 </Tabs>
 
-### Referring to Common Configuration
+### Using Common Configuration Across Components
 
-Referencing common configuration from multiple components is easy and safe with
-Holos and CUE.
+Referencing common configuration across multiple components is straightforward
+and reliable using Holos and CUE.
 
-Patch the two `values.cue` files, or edit them by hand, to reference
-`Blackbox.host` and `Blackbox.port`.
+To apply the common configuration, patch the two `values.cue` files, or manually
+edit them to reference `Blackbox.host` and `Blackbox.port`.
 
 <Tabs groupId="5FFCE892-B8D4-4F5B-B2E2-39EC9E9F87A4">
   <TabItem value="command" label="Command">
@@ -379,13 +373,13 @@ git add . && git commit -m 'integrate blackbox and prometheus together'
 
 ## Reviewing Changes
 
-Holos makes it easy to see and review platform wide changes.  Render the
-platform to see how both prometheus and blackbox change in lock step.
+Holos makes it easy to view and review platform-wide changes. Render the
+platform to observe how both Prometheus and Blackbox update in sync.
 
 <Tabs groupId="E7F6D8B1-22FA-4075-9B44-D9F2815FE0D3">
   <TabItem value="command" label="Command">
 ```bash
-holos render platform ./platform
+holos render platform
 ```
   </TabItem>
   <TabItem value="output" label="Output">
@@ -397,7 +391,7 @@ rendered platform in 383.270625ms
   </TabItem>
 </Tabs>
 
-Changes are easily visible with version control.
+Changes are easily visible in version control.
 
 <Tabs groupId="9789A0EF-24D4-4FB9-978A-3895C2778789">
   <TabItem value="command" label="Command">
@@ -476,19 +470,18 @@ index 9e02bce..ab638f0 100644
   </TabItem>
 </Tabs>
 
-From the diff we know this change will:
+From the diff, we can see this change will:
 
-1. Reconfigure the blackbox exporter host from `prometheus-blackbox-exporter` to `blackbox`.
-2. Have no effect on the blackbox service port.  It was already using the default 9115.
-3. Reconfigure prometheus to query the blackbox exporter at the correct host and
-port, `blackbox:9115`.
+1. Reconfigure the Blackbox Exporter host from `prometheus-blackbox-exporter` to `blackbox`.
+2. Have no effect on the Blackbox service port, as it was already using the default `9115`.
+3. Reconfigure Prometheus to query the Blackbox Exporter at the correct host and port, `blackbox:9115`.
 
-Without this change prometheus incorrectly assumed blackbox was listening at
+Without this change, Prometheus incorrectly assumed Blackbox was listening at
 `blackbox` on port `80` when it was actually listening at
-`prometheus-blackbox-exporter` port `9115`.  Going forward, changing the
-blackbox host or port will reconfigure both charts correctly.
+`prometheus-blackbox-exporter` on port `9115`. Going forward, changing the
+Blackbox host or port will reconfigure both charts correctly.
 
-Commit the changes and move on to deploying them.
+Commit the changes and proceed to deploy them.
 
 <Tabs groupId="F8C9A98D-DE1E-4EF6-92C1-017A9166F6C7">
   <TabItem value="command" label="Command">
@@ -506,14 +499,15 @@ git add . && git commit -m 'render integrated blackbox and prometheus manifests'
 
 ## Trying Locally
 
-Optionally apply the manifests Holos rendered to a [Local Cluster].
+Optionally, apply the manifests rendered by Holos to a [Local Cluster].
 
 ## Next Steps
 
-In this tutorial we learned how Holos makes it easier to holistically integrate
-the [prometheus] and [blackbox] charts so they're configured in lock step with
-each other.  If we relied on Helm alone, there is no good way to configure both
-charts to use the same service endpoint.
+In this tutorial, we learned how Holos simplifies the holistic integration of
+the [prometheus] and [blackbox] charts, ensuring they are configured
+consistently. By using Holos, we overcome the limitations of relying solely on
+Helm, which lacks an effective method to configure both charts to use the same
+service endpoint.
 
 [rendered manifests pattern]: https://akuity.io/blog/the-rendered-manifests-pattern
 [prometheus]: https://github.com/prometheus-community/helm-charts/tree/prometheus-25.27.0/charts/prometheus

doc/md/tutorial/kustomize.mdx

@@ -12,14 +12,14 @@ import TabItem from '@theme/TabItem';
 
 ## Overview
 
-In the previous tutorial we learned how Holos makes it easier to holistically
-integrate the [prometheus] and [blackbox] charts so they're configured in lock
-step with each other.
+In the previous tutorial, we learned how Holos simplifies the holistic
+integration of the [prometheus] and [blackbox] charts, ensuring they are
+configured in sync.
 
-This tutorial goes further by integrating the [httpbin] service with prometheus
-and blackbox to automatically probe for availability.
+In this tutorial, we'll go a step further by integrating the [httpbin] service
+with Prometheus and Blackbox to automatically probe for availability.
 
-We'll explore how Holos manages [kustomize] bases similar to the Helm kind
+We'll also explore how Holos manages [kustomize] bases, similar to the Helm kind
 covered in the [Helm Values] tutorial.
 
 ## The Code
@@ -34,8 +34,10 @@ Otherwise click the **Generate** tab to generate a blank platform now.
 :::
   </TabItem>
   <TabItem value="generate" label="Generate">
-Use `holos` to generate a minimal platform directory structure.  First, create
-and cd into a blank directory. Then use the `holos init platform` command.
+
+Use `holos` to generate a minimal platform directory structure. First, create
+and navigate into a blank directory. Then, run the `holos init platform`
+command.
 
 ```shell
 mkdir holos-kustomize-tutorial
@@ -54,8 +56,8 @@ git init . && git add . && git commit -m initial
 
 ### Managing the Component
 
-Create the `httpbin` component directory and add the `httpbin.cue` and
-`httpbin.yaml` files to it.
+Create the `httpbin` component directory, and add the `httpbin.cue` and
+`httpbin.yaml` files to it for configuration and setup.
 
 <Tabs groupId="800C3AE7-E7F8-4AFC-ABF1-6AFECD945958">
   <TabItem value="setup" label="Setup">
@@ -154,9 +156,9 @@ EOF
 Holos knows the `httpbin.yaml` file is part of the BuildPlan because of the
 `KustomizeConfig: Files: "httpbin.yaml": _` line in the `httpbin.cue`.
 
-### Integrating the Components
+### Register the Components
 
-Integrate `httpbin` with the platform by adding the following file to the
+Register `httpbin` with the platform by adding the following file to the
 platform directory.
 
 ```bash
@@ -181,7 +183,7 @@ Render the platform.
 <Tabs groupId="B120D5D1-0EAB-41E0-AD21-15526EBDD53D">
   <TabItem value="command" label="Command">
 ```bash
-holos render platform ./platform
+holos render platform
 ```
   </TabItem>
   <TabItem value="output" label="Output">
@@ -212,10 +214,10 @@ git add . && git commit -m 'add httpbin'
   </TabItem>
 </Tabs>
 
-### Inspecting the BuildPlan
+### Inspecting the Build Plan
 
 We can see the [BuildPlan] exported to `holos` by the `holos:
-Kustomize.BuildPlan` line in `httpbin.cue`.  Holos processes this build plan to
+Kustomize.BuildPlan` line in `httpbin.cue`. Holos processes this build plan to
 produce the fully rendered manifests.
 
 <Tabs groupId="DD697D65-5BEC-4B92-BB33-59BE4FEC112F">
@@ -270,19 +272,21 @@ source:
   </TabItem>
 </Tabs>
 
-### Transforming manifests
+### Transforming Manifests
 
-Reviewing the BuildPlan exported in the previous command:
+Review the BuildPlan exported in the previous command:
 
 1. The [File Generator] copies the plain `httpbin.yaml` file into the build.
 2. The [Kustomize Transformer] uses `httpbin.yaml` as an input resource.
 3. The final artifact is the output from Kustomize.
 
-This BuildPlan transforms the raw yaml by labeling all of the resources with
+This BuildPlan transforms the raw YAML by labeling all of the resources with
 `"app.kubernetes.io/name": "httpbin"` using the [KustomizeConfig] `CommonLabels`
-field.  We still need to integrate `httpbin` with `prometheus`.   Annotate the
-Service with `prometheus.io/probe: "true"` to complete the integration.  Holos
-makes this easier with CUE.  We don't need to edit any yaml files.
+field.
+
+To complete the integration with Prometheus, annotate the Service with
+`prometheus.io/probe: "true"`. Holos makes this easier with CUE, so there's no
+need to edit any YAML files manually.
 
 Add a new `patches.cue` file to the `httpbin` component with the following
 content.
@@ -324,7 +328,7 @@ Render the platform to see the result of the kustomization patch.
 <Tabs groupId="5D1812DD-8E7B-4F97-B349-275214F38B6E">
   <TabItem value="command" label="Command">
 ```bash
-holos render platform ./platform
+holos render platform
 ```
   </TabItem>
   <TabItem value="output" label="Output">
@@ -382,17 +386,19 @@ git add . && git commit -m 'annotate httpbin for prometheus probes'
 
 ## Trying Locally
 
-Optionally apply the manifests Holos rendered to a [Local Cluster].
+Optionally, apply the manifests rendered by Holos to a [Local Cluster] for
+testing and validation.
 
 ## Next Steps
 
-We learned how Holos makes it easier to manage [httpbin], distributed as a
-Kustomize base, using a kustomize Component similar to the helm component we saw
-previously.  Holos offers a clear way to kustomize any component, patching an
-annotation onto the `httpbin` Service in this example.
+In this tutorial, we learned how Holos simplifies managing [httpbin], which is
+distributed as a Kustomize base. We used a Kustomize component similar to the
+Helm component covered previously. Holos provides a straightforward way to
+customize any component, demonstrated by patching an annotation onto the
+`httpbin` Service.
 
-Continue on with the tutorial to explore how Holos makes it easier to manage
-certificates and make services accessible outside of a cluster.
+Continue with the tutorial to learn how Holos facilitates certificate management
+and makes services accessible outside of a cluster.
 
 [httpbin]: https://github.com/mccutchen/go-httpbin/tree/v2.15.0
 [prometheus]: https://github.com/prometheus-community/helm-charts/tree/prometheus-25.27.0/charts/prometheus

doc/md/tutorial/overview.mdx

@@ -11,19 +11,16 @@ import RenderingOverview from '@site/src/diagrams/rendering-overview.mdx';
 
 ## Overview
 
-Holos is a configuration management tool for Kubernetes resources.  It provides
-the building blocks needed for implementing the [rendered manifests pattern].
-It gives the flexibility to manage a wide range of configurations, from large
-software delivery platforms spanning multiple clusters and regions to generating
-a single resource on your local device.
+Holos is a configuration management tool for Kubernetes implementing the
+[rendered manifests pattern]. It handles configurations ranging from single
+resources to multi-cluster platforms across regions.
 
 {/* truncate */}
 
-At a high level, Holos provides a few major components:
-
-- A Platform schema for specifying how components integrate together into a platform.
-- Component building blocks for Helm, Kustomize, and Kubernetes to unify configuration with CUE.
-- A BuildPlan orchestrating generators, transformers, and validators to produce manifest files.
+Key components:
+- Platform schemas defining component integration
+- Building blocks unifying Helm, Kustomize and Kubernetes configs with CUE
+- BuildPlan pipeline for generating, transforming and validating manifests
 
 <RenderingOverview />
 
@@ -31,43 +28,39 @@ At a high level, Holos provides a few major components:
 
 ## Holos' role in your organization
 
-Platform engineers run the `holos render platform` command locally and in CI to
-produce Kubernetes manifests which are committed to version control.  GitOps
-tools like ArgoCD or Flux deploy the manifests produced by Holos.
+Platform engineers use Holos to generate Kubernetes manifests, both locally and
+in CI pipelines. The manifests are committed to version control and deployed via
+GitOps tools like ArgoCD or Flux.
 
-Holos works well with your existing Helm charts, kustomize bases, and any other
-configuration data you currently store in version control.
+Holos integrates seamlessly with existing Helm charts, Kustomize bases, and
+other version-controlled configurations.
 
 ## Advantages of Holos
 
 ### Safe
 
-Holos uses [CUE] to provide strong typing and constraints to configuration data.
-Additionally, holos adds strong validation to verify the output produced by Helm
-and other tools.
+Holos leverages [CUE] for strong typing and validation of configuration data,
+ensuring consistent output from Helm and other tools.
 
 ### Consistent
 
-Holos offers a consistent way to incorporate a wide variety of tools into a well
-defined data pipeline.  Configuration produced from CUE, Helm, and Kustomize are
-all handled with the same consistent process.
+A unified pipeline processes all configurations - whether from CUE, Helm, or
+Kustomize - through the same well-defined stages.
 
 ### Flexible
 
-Holos is designed to be flexible.  Holos offers flexible building blocks for
-data generation, transformation, validation, and integration.  Find the perfect
-fit for your team by assembling these building blocks to your unique needs.
+Composable building blocks for generation, transformation, validation and
+integration let teams assemble workflows that match their needs.
 
-Holos does not have an opinion on many common aspects of platform configuration.
-For example, environments and clusters are explicitly kept out of the core and
-instead are provided as flexible, user-customizable [topics] organized as a
-recipes.
+The core is intentionally unopinionated about platform configuration patterns.
+Common needs like environments and clusters are provided as customizable
+[topics] recipes rather than enforced structures.
 
 ## Getting Help
 
-If you get stuck, you can get help on [Discord] or [GitHub discussions].  Don't
-worry about asking "beginner" questions, configuration is often complex even for
-the most experienced among us.  We all start somewhere and are happy to help.
+Get support through our [Discord] channel or [GitHub discussions]. Configuration
+challenges arise at all experience levels - we welcome your questions and are
+here to help.
 
 [rendered manifests pattern]: https://akuity.io/blog/the-rendered-manifests-pattern
 [CUE]: https://cuelang.org/

doc/md/tutorial/setup.mdx

@@ -11,22 +11,23 @@ import RenderPlatformDiagram from '@site/src/diagrams/render-platform-sequence.m
 
 # Setup
 
-## Overview
-
-This tutorial will guide you through the installation of Holos and its
-dependencies, as well as the initialization of a minimal Platform that you can
-extend to meet your specific needs.
-
 ## Installing
 
-Holos is distributed as a single file executable that can be installed in a
-couple of ways.
+Holos is a single executable that can be installed via:
 
 <Tabs groupId="FE2C74C8-B3A3-4AEA-BBD3-F57FAA654B6F">
-  <TabItem value="brew" label="Install with brew">
+  <TabItem value="brew" label="macOS">
 ```bash
 brew install holos-run/tap/holos
 ```
+  </TabItem>
+  <TabItem value="linux" label="Linux">
+Download holos from the [releases] page and place the executable into your shell
+path.
+  </TabItem>
+  <TabItem value="win" label="Windows">
+Download holos from the [releases] page and place the executable into your shell
+path.
   </TabItem>
   <TabItem value="go" label="Go">
 ```bash
@@ -60,31 +61,22 @@ holos completion powershell | Invoke-Expression
   </TabItem>
 </Tabs>
 
-### Releases
-
-Download `holos` from the [releases] page and place the executable into your
-shell path.
-
 ### Dependencies
 
-Holos integrates with the following tools that should be installed to enable
-their functionality.
+Install these tools to use Holos's full capabilities:
 
-- [Helm] to fetch and render Helm chart Components.
-- [Kubectl] to [kustomize] components.
+- [Helm] for chart management and rendering
+- [Kubectl] for [kustomize] operations
 
 :::note
-Holos is tested with Helm version `v3.16.2`.
+Holos is tested with Helm `v3.16.2`. If you see `Error: chart requires
+kubeVersion` errors, try upgrading Helm.
 :::
 
-Please try upgrading helm if you encounter `Error: chart requires kubeVersion
-...` errors.
-
 ## Next Steps
 
-You've got the structure of your platform configuration in place. Continue on to
-[Hello Holos] where you'll learn how easy it is to manage a Helm chart with
-holos.
+With your platform structure initialized, proceed to [Hello Holos] to learn Helm
+chart management.
 
 [Helm]: https://github.com/helm/helm/releases
 [Kubectl]: https://kubernetes.io/docs/tasks/tools/

doc/md/tutorial/validators.mdx

@@ -0,0 +1,428 @@
+---
+slug: validators
+title: Validators
+description: Validate rendered manifests against policy definitions.
+sidebar_position: 60
+---
+
+import Tabs from '@theme/Tabs';
+import TabItem from '@theme/TabItem';
+import RenderingOverview from '@site/src/diagrams/rendering-overview.mdx';
+
+# Validators
+
+## Overview
+
+Sometimes Helm charts render Secrets we do not wanted committed to version
+control for security.  Helm charts often render incorrect manifests, even if
+they're accepted by the api server.  For example, passing `null` to collection
+fields.  We'll solve both of these issues using a [Validator] to block artifacts
+with a Secret resource, and verifying the artifact against Kubernetes type
+definitions.
+
+1. If a Helm chart renders a Secret, Holos errors before writing the artifact
+and suggests an ExternalSecret instead.
+2. Each resource is validated against a field named by the value of the kind
+field.  For example, a `kind: Secret` resource validates against `secret: {}` in
+CUE.  `kind: Deployment` validates against `deployment: {}` in CUE.
+3. The final artifact is validated, covering the output of all generators and
+transformers.
+
+<RenderingOverview />
+
+## The Code
+
+### Generating the Structure
+
+Use `holos` to generate a minimal platform directory structure. First, create
+and navigate into a blank directory. Then, use the `holos generate platform`
+command to generate a minimal platform.
+
+```shell
+mkdir holos-validators-tutorial && cd holos-validators-tutorial
+holos init platform v1alpha5
+```
+
+### Creating the Component
+
+Create the directory for the `podinfo` component. Create an empty file, then add
+the following CUE configuration to it.
+
+```bash
+mkdir -p components/podinfo
+```
+```bash
+cat <<EOF > components/podinfo/podinfo.cue
+```
+```cue showLineNumbers
+package holos
+
+// export the component build plan to holos
+holos: Component.BuildPlan
+
+// Component is a Helm chart
+Component: #Helm & {
+	Name:      "podinfo"
+	Namespace: "default"
+	// Add metadata.namespace to all resources with kustomize.
+	KustomizeConfig: Kustomization: namespace: Namespace
+	Chart: {
+		version: "6.6.2"
+		repository: {
+			name: "podinfo"
+			url:  "https://stefanprodan.github.io/podinfo"
+		}
+	}
+}
+```
+```bash
+EOF
+```
+
+Register the component with the platform.
+
+```bash
+cat <<EOF > platform/podinfo.cue
+```
+```cue showLineNumbers
+package holos
+
+Platform: Components: podinfo: {
+	name: "podinfo"
+	path: "components/podinfo"
+}
+```
+```bash
+EOF
+```
+
+Render the platform.
+
+<Tabs groupId="tutorial-hello-render-manifests">
+  <TabItem value="command" label="Command">
+```bash
+holos render platform
+```
+  </TabItem>
+  <TabItem value="output" label="Output">
+```
+cached podinfo 6.6.2
+rendered podinfo in 1.938665041s
+rendered platform in 1.938759417s
+```
+  </TabItem>
+</Tabs>
+
+Add and commit the initial configuration.
+
+```bash
+git init . && git add . && git commit -m initial
+```
+
+### Define the Valid Schema
+
+We'll use a CUE package named `policy` so the entire platform configuration in
+package `holos` isn't loaded every time we validate an artifact.
+
+Create `policy/validation-schema.cue` with the following content.
+
+```shell
+mkdir -p policy
+cat <<EOF > policy/validation-schema.cue
+```
+```cue showLineNumbers
+package policy
+
+import apps "k8s.io/api/apps/v1"
+
+// Organize by kind then name to avoid conflicts.
+kind: [KIND=string]: [NAME=string]: {...}
+
+// Useful when one component manages the same resource kind and name across
+// multiple namespaces.
+let KIND = kind
+namespace: [NS=string]: KIND
+
+// Block Secret resources. kind will not unify with "Secret"
+kind: secret: [NAME=string]: kind: "Use an ExternalSecret instead.  Forbidden by security policy.  secret/\(NAME)"
+
+// Validate Deployment against Kubernetes type definitions.
+kind: deployment: [_]: apps.#Deployment
+```
+```shell
+EOF
+```
+
+### Configuring Validators
+
+Configure the Validators [ComponentConfig] field to configure each [BuildPlan]
+to validate the rendered [Artifact] files.
+
+```shell
+cat <<EOF > validators.cue
+```
+```cue showLineNumbers
+package holos
+
+// Configure all component kinds to validate against the policy directory.
+#ComponentConfig: Validators: cue: {
+	kind: "Command"
+	// Note --path maps each resource to a top level field named by the kind.
+	command: args: [
+		"holos",
+		"cue",
+		"vet",
+		"./policy",
+		"--path=\"namespace\"",
+		"--path=metadata.namespace",
+		"--path=strings.ToLower(kind)",
+		"--path=metadata.name",
+	]
+}
+```
+```shell
+EOF
+```
+
+### Patching Errors
+
+Render the platform to see validation fail.  The podinfo chart has no Secret,
+but it produces an invalid Deployment because it sets the container resource
+limits field to `null`.
+
+```shell
+holos render platform
+```
+
+```txt
+deployment.spec.template.spec.containers.0.resources.limits: conflicting values null and {[string]:"k8s.io/apimachinery/pkg/api/resource".#Quantity} (mismatched types null and struct):
+    ./cue.mod/gen/k8s.io/api/apps/v1/types_go_gen.cue:355:9
+    ./cue.mod/gen/k8s.io/api/apps/v1/types_go_gen.cue:376:12
+    ./cue.mod/gen/k8s.io/api/core/v1/types_go_gen.cue:2840:11
+    ./cue.mod/gen/k8s.io/api/core/v1/types_go_gen.cue:2968:14
+    ./cue.mod/gen/k8s.io/api/core/v1/types_go_gen.cue:3882:15
+    ./cue.mod/gen/k8s.io/api/core/v1/types_go_gen.cue:3882:18
+    ./cue.mod/gen/k8s.io/api/core/v1/types_go_gen.cue:5027:9
+    ./cue.mod/gen/k8s.io/api/core/v1/types_go_gen.cue:6407:16
+    ./policy/validation-schema.cue:9:13
+    ../../../../../var/folders/22/T/holos.validate1636392304/components/podinfo/podinfo.gen.yaml:104:19
+could not run: terminating because of errors
+could not run: could not validate podinfo path ./components/podinfo: could not run command: holos cue vet ./policy --path strings.ToLower(kind) /var/folders/22/T/holos.validate1636392304/components/podinfo/podinfo.gen.yaml: exit status 1 at builder/v1alpha5/builder.go:411
+could not run: could not render component: could not run command: holos --log-level info --log-format console render component --inject holos_component_name=podinfo --inject holos_component_path=components/podinfo ./components/podinfo: exit status 1 at cli/render/render.go:155
+```
+
+We'll use a [Kustomize] patch [Transformer] to replace the `null` limits field
+with a valid equivalent value.
+
+:::important
+This configuration is defined in CUE, not YAML, even though we're configuring a
+Kustomize patch transformer.  CUE gives us access to the unified platform
+configuration.
+:::
+
+```shell
+cat <<EOF > components/podinfo/patch.cue
+```
+```cue showLineNumbers
+package holos
+
+import "encoding/yaml"
+
+Component: KustomizeConfig: Kustomization: {
+	_patches: limits: {
+		target: kind: "Deployment"
+		patch: yaml.Marshal([{
+			op:    "test"
+			path:  "/spec/template/spec/containers/0/resources/limits"
+			value: null
+		}, {
+			op:   "replace"
+			path: "/spec/template/spec/containers/0/resources/limits"
+			value: {}
+		}])
+	}
+	patches: [for x in _patches {x}]
+}
+```
+```shell
+EOF
+```
+
+Now the platform renders.
+
+<Tabs groupId="3A050092-8E56-49D4-84A9-71E544A21276">
+  <TabItem value="command" label="Command">
+```bash
+holos render platform
+```
+  </TabItem>
+  <TabItem value="output" label="Output">
+```txt
+rendered podinfo in 181.875083ms
+rendered platform in 181.975833ms
+```
+  </TabItem>
+</Tabs>
+
+## Inspecting the BuildPlan
+
+The BuildPlan patches the output of the upstream helm chart without modifying
+it, then validates the artifact against the Kubernetes type definitions.
+
+<Tabs groupId="1DAB4C46-0793-4CCA-8930-7B2E60BDA1BE">
+  <TabItem value="command" label="Command">
+```bash
+holos show buildplans
+```
+  </TabItem>
+  <TabItem value="output" label="Output">
+```yaml showLineNumbers
+kind: BuildPlan
+apiVersion: v1alpha5
+metadata:
+  name: podinfo
+spec:
+  artifacts:
+    - artifact: components/podinfo/podinfo.gen.yaml
+      generators:
+        - kind: Helm
+          output: helm.gen.yaml
+          helm:
+            chart:
+              name: podinfo
+              version: 6.6.2
+              release: podinfo
+              repository:
+                name: podinfo
+                url: https://stefanprodan.github.io/podinfo
+            values: {}
+            namespace: default
+        - kind: Resources
+          output: resources.gen.yaml
+      transformers:
+        - kind: Kustomize
+          inputs:
+            - helm.gen.yaml
+            - resources.gen.yaml
+          output: components/podinfo/podinfo.gen.yaml
+          kustomize:
+            kustomization:
+              apiVersion: kustomize.config.k8s.io/v1beta1
+              kind: Kustomization
+              namespace: default
+              patches:
+                - patch: |
+                    - op: test
+                      path: /spec/template/spec/containers/0/resources/limits
+                      value: null
+                    - op: replace
+                      path: /spec/template/spec/containers/0/resources/limits
+                      value: {}
+                  target:
+                    kind: Deployment
+                    name: ""
+              resources:
+                - helm.gen.yaml
+                - resources.gen.yaml
+      validators:
+        - kind: Command
+          inputs:
+            - components/podinfo/podinfo.gen.yaml
+          command:
+            args:
+              - holos
+              - cue
+              - vet
+              - ./policy
+              - --path
+              - strings.ToLower(kind)
+```
+  </TabItem>
+</Tabs>
+
+## Catching Mistakes
+
+Suppose a teammate downloads a helm chart that includes a Secret unbeknown to
+them.  Holos catches the problem and suggests an ExternalSecret instead.
+
+Mix in a Secret to see what happens
+
+```shell
+cat <<EOF > components/podinfo/secret.cue
+```
+```cue showLineNumbers
+package holos
+
+Component: Resources: Secret: example: metadata: name: "example"
+```
+```shell
+EOF
+```
+
+Render the platform to see the error.
+
+```shell
+holos render platform
+```
+```txt
+secret.kind: conflicting values "Use an ExternalSecret instead.  Forbidden by security policy." and "Secret":
+    ./policy/validation-schema.cue:6:15
+    ../../../../../var/folders/22/T/holos.validate2549739170/components/podinfo/podinfo.gen.yaml:1:7
+could not run: terminating because of errors
+could not run: could not validate podinfo path ./components/podinfo: could not run command: holos cue vet ./policy --path strings.ToLower(kind) /var/folders/22/T/holos.validate2549739170/components/podinfo/podinfo.gen.yaml: exit status 1 at builder/v1alpha5/builder.go:411
+could not run: could not render component: could not run command: holos --log-level info --log-format console render component --inject holos_component_name=podinfo --inject holos_component_path=components/podinfo ./components/podinfo: exit status 1 at cli/render/render.go:155
+```
+
+:::important
+Holos quickly returns an error if validated artifacts have a Secret.
+:::
+
+Remove the secret to resolve the issue.
+
+```shell
+rm components/podinfo/secret.cue
+```
+
+## Inspecting the diff
+
+The validation and patch results in a correct Deployment, verified against the
+Kubernetes type definitions.
+
+```shell
+git diff
+```
+```diff
+diff --git a/deploy/components/podinfo/podinfo.gen.yaml b/deploy/components/podinfo/podinfo.gen.yaml
+index 6e4aec0..a145e3f 100644
+--- a/deploy/components/podinfo/podinfo.gen.yaml
++++ b/deploy/components/podinfo/podinfo.gen.yaml
+@@ -101,7 +101,7 @@ spec:
+           successThreshold: 1
+           timeoutSeconds: 5
+         resources:
+-          limits: null
++          limits: {}
+           requests:
+             cpu: 1m
+             memory: 16Mi
+```
+
+## Trying Locally
+
+Optionally, apply the manifests rendered by Holos to a [Local Cluster] for
+testing.
+
+[Local Cluster]: ../topics/local-cluster.mdx
+[ExternalSecret]: https://external-secrets.io/latest/api/externalsecret/
+[Artifact]: ../api/core.md#Artifact
+[BuildPlan]: ../api/core.md#BuildPlan
+[Resources]: ../api/core.md#Resources
+[Validator]: ../api/core.md#Validator
+[Transformer]: ../api/core.md#Transformer
+[Kustomize]: ../api/core.md#Kustomize
+[Generator]: ../api/core.md#Generator
+[Hello Holos]: ./hello-holos.mdx
+[cue.mod/gen/external-secrets.io/externalsecret/v1beta1/types_gen.cue]: https://github.com/holos-run/holos/blob/main/internal/generate/platforms/cue.mod/gen/external-secrets.io/externalsecret/v1beta1/types_gen.cue#L13
+[ComponentConfig]: ../api/author.md#ComponentConfig
+[timoni]: https://timoni.sh/install/
+[resources.cue]: https://github.com/holos-run/holos/blob/main/internal/generate/platforms/v1alpha5/resources.cue#L33

doc/website/blog/2024-11-25-validators.mdx

@@ -0,0 +1,35 @@
+---
+slug: validators-feature
+title: Validators added in Holos v0.101.0
+authors: [jeff]
+tags: [holos, feature]
+image: /img/cards/validators.png
+description: Validators are useful to enforce policy and catch Helm errors.
+---
+
+import RenderingOverview from '@site/src/diagrams/rendering-overview.mdx';
+import RenderPlatformDiagram from '@site/src/diagrams/render-platform-sequence.mdx';
+
+We've added support for [Validators] in [v0.101.0].  Validators are useful to
+enforce policies and ensure consistency early in the process.  This feature
+addresses two primary use cases:
+
+1. Prevent insecure configuration early in the process.  For example, prevent
+Helm from rendering a `Secret` which would otherwise be committed to version control.
+2. Prevent unsafe configuration by validating manifests against Kubernetes core
+and custom resource type definitions.
+
+Check out the [Validators] tutorial for examples of both use cases.
+
+[Validators]: https://holos.run/docs/v1alpha5/tutorial/validators/
+[v0.101.0]: https://github.com/holos-run/holos/releases/tag/v0.101.0
+
+{/* truncate */}
+
+<RenderingOverview />
+
+Validators complete the core functionality of the Holos manifest rendering
+pipeline.  We are seeking design partners to help enhance Generators and
+Transformers.  Validators are implemented using a generic `Command` kind, and
+we're considering a similar kind for Generators and Transformers.  Please
+connect with us if you'd like to help design these enhancements.

doc/website/src/diagrams/rendering-overview.mdx

@@ -3,21 +3,21 @@
 title: Rendering Overview
 ---
 graph LR
-    Platform[<a href="/docs/v1alpha5/api/author/#Platform">Platform</a>]
-    Component[<a href="/docs/v1alpha5/api/author/#ComponentConfig">Components</a>]
+    Platform[<a href="https://holos.run/docs/v1alpha5/api/author/#Platform">Platform</a>]
+    Component[<a href="https://holos.run/docs/v1alpha5/api/author/#ComponentConfig">Components</a>]
 
-    Helm[<a href="/docs/v1alpha5/api/author/#Helm">Helm</a>]
-    Kustomize[<a href="/docs/v1alpha5/api/author/#Kustomize">Kustomize</a>]
-    Kubernetes[<a href="/docs/v1alpha5/api/author/#Kubernetes">Kubernetes</a>]
+    Helm[<a href="https://holos.run/docs/v1alpha5/api/author/#Helm">Helm</a>]
+    Kustomize[<a href="https://holos.run/docs/v1alpha5/api/author/#Kustomize">Kustomize</a>]
+    Kubernetes[<a href="https://holos.run/docs/v1alpha5/api/author/#Kubernetes">Kubernetes</a>]
 
-    BuildPlan[<a href="/docs/v1alpha5/api/core/#BuildPlan">BuildPlan</a>]
+    BuildPlan[<a href="https://holos.run/docs/v1alpha5/api/core/#BuildPlan">BuildPlan</a>]
 
-    ResourcesArtifact[<a href="/docs/v1alpha5/api/core/#Artifact">Resources<br/>Artifact</a>]
-    GitOpsArtifact[<a href="/docs/v1alpha5/api/core/#Artifact">GitOps<br/>Artifact</a>]
+    ResourcesArtifact[<a href="https://holos.run/docs/v1alpha5/api/core/#Artifact">Resources<br/>Artifact</a>]
+    GitOpsArtifact[<a href="https://holos.run/docs/v1alpha5/api/core/#Artifact">GitOps<br/>Artifact</a>]
 
-    Generators[<a href="/docs/v1alpha5/api/core/#Generator">Generators</a>]
-    Transformers[<a href="/docs/v1alpha5/api/core/#Transformer">Transformers</a>]
-    Validators[Validators]
+    Generators[<a href="https://holos.run/docs/v1alpha5/api/core/#Generator">Generators</a>]
+    Transformers[<a href="https://holos.run/docs/v1alpha5/api/core/#Transformer">Transformers</a>]
+    Validators[<a href="https://holos.run/docs/v1alpha5/api/core/#Validator">Validators</a>]
     Files[Manifest<br/>Files]
 
     Platform --> Component

doc/website/static/_redirects

@@ -0,0 +1,14 @@
+/docs                /docs/v1alpha5/ 301
+/docs/               /docs/v1alpha5/ 301
+/docs/tutorial       /docs/v1alpha5/tutorial/ 301
+/docs/tutorial/      /docs/v1alpha5/tutorial/ 301
+/docs/quickstart     /docs/v1alpha5/tutorial/overview/ 301
+/docs/quickstart/    /docs/v1alpha5/tutorial/overview/ 301
+/docs/overview       /docs/v1alpha5/tutorial/overview/ 301
+/docs/overview/      /docs/v1alpha5/tutorial/overview/ 301
+/docs/topics         /docs/v1alpha5/topics/structures/ 301
+/docs/topics/        /docs/v1alpha5/topics/structures/ 301
+/docs/setup          /docs/v1alpha5/tutorial/setup/ 301
+/docs/setup/         /docs/v1alpha5/tutorial/setup/ 301
+/docs/local-cluster  /docs/v1alpha5/topics/local-cluster/ 301
+/docs/local-cluster/ /docs/v1alpha5/topics/local-cluster/ 301

internal/artifact/artifact.go

@@ -20,6 +20,7 @@ var _ Store = NewStore()
 type Store interface {
 	Get(path string) (data []byte, ok bool)
 	Set(path string, data []byte) error
+	// Save previously set path to dir preserving directories.
 	Save(dir, path string) error
 }
 

internal/builder/platform.go

@@ -15,7 +15,7 @@ import (
 // PlatformOpts represents build options when processing the components in a
 // platform.
 type PlatformOpts struct {
-	Fn          BuildFunc
+	Fn          func(context.Context, int, holos.Component) error
 	Selector    holos.Selector
 	Concurrency int
 	InfoEnabled bool
@@ -89,9 +89,6 @@ func (p *Platform) Build(ctx context.Context, opts PlatformOpts) error {
 	return nil
 }
 
-// BuildFunc is executed concurrently when processing platform components.
-type BuildFunc func(context.Context, int, holos.Component) error
-
 func LoadPlatform(i *Instance) (platform Platform, err error) {
 	err = i.Discriminate(func(tm holos.TypeMeta) error {
 		if tm.Kind != "Platform" {

internal/builder/v1alpha5/builder.go

@@ -5,16 +5,17 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"io"
 	"log/slog"
 	"os"
 	"path/filepath"
 	"strings"
+	"sync"
 	"syscall"
 	"time"
 
 	"cuelang.org/go/cue"
 	core "github.com/holos-run/holos/api/core/v1alpha5"
-	"github.com/holos-run/holos/internal/artifact"
 	"github.com/holos-run/holos/internal/errors"
 	"github.com/holos-run/holos/internal/holos"
 	"github.com/holos-run/holos/internal/logger"
@@ -107,156 +108,84 @@ func (c *Component) Path() string {
 }
 
 var _ holos.BuildPlan = &BuildPlan{}
+var _ task = generatorTask{}
+var _ task = transformersTask{}
+var _ task = validatorTask{}
 
-// BuildPlan represents a component builder.
-type BuildPlan struct {
-	core.BuildPlan
-	Opts holos.BuildOpts
+type task interface {
+	id() string
+	run(ctx context.Context) error
 }
 
-// Build builds a BuildPlan into Artifact files.
-func (b *BuildPlan) Build(ctx context.Context) error {
-	name := b.BuildPlan.Metadata.Name
-	path := b.Opts.Path
-	log := logger.FromContext(ctx).With("name", name, "path", path)
-	msg := fmt.Sprintf("could not build %s", name)
-	if b.BuildPlan.Spec.Disabled {
-		log.WarnContext(ctx, fmt.Sprintf("%s: disabled", msg))
-		return nil
-	}
+type taskParams struct {
+	taskName      string
+	buildPlanName string
+	opts          holos.BuildOpts
+}
 
-	g, ctx := errgroup.WithContext(ctx)
-	// One more for the producer
-	g.SetLimit(b.Opts.Concurrency + 1)
+func (t taskParams) id() string {
+	return fmt.Sprintf("%s:%s/%s", t.opts.Path, t.buildPlanName, t.taskName)
+}
 
-	// Producer.
-	g.Go(func() error {
-		for _, a := range b.BuildPlan.Spec.Artifacts {
-			msg := fmt.Sprintf("%s artifact %s", msg, a.Artifact)
-			log := log.With("artifact", a.Artifact)
-			if a.Skip {
-				log.WarnContext(ctx, fmt.Sprintf("%s: skipped field is true", msg))
-				continue
-			}
-			select {
-			case <-ctx.Done():
-				return ctx.Err()
-			default:
-				// https://golang.org/doc/faq#closures_and_goroutines
-				a := a
-				// Worker.  Blocks if limit has been reached.
-				g.Go(func() error {
-					for _, gen := range a.Generators {
-						switch gen.Kind {
-						case "Resources":
-							if err := b.resources(log, gen, b.Opts.Store); err != nil {
-								return errors.Format("could not generate resources: %w", err)
-							}
-						case "Helm":
-							if err := b.helm(ctx, log, gen, b.Opts.Store); err != nil {
-								return errors.Format("could not generate helm: %w", err)
-							}
-						case "File":
-							if err := b.file(log, gen, b.Opts.Store); err != nil {
-								return errors.Format("could not generate file: %w", err)
-							}
-						default:
-							return errors.Format("%s: unsupported kind %s", msg, gen.Kind)
-						}
-					}
+type generatorTask struct {
+	taskParams
+	generator core.Generator
+	wg        *sync.WaitGroup
+}
 
-					for _, t := range a.Transformers {
-						switch t.Kind {
-						case "Kustomize":
-							if err := b.kustomize(ctx, log, t, b.Opts.Store); err != nil {
-								return errors.Wrap(err)
-							}
-						case "Join":
-							s := make([][]byte, 0, len(t.Inputs))
-							for _, input := range t.Inputs {
-								if data, ok := b.Opts.Store.Get(string(input)); ok {
-									s = append(s, data)
-								} else {
-									return errors.Format("%s: missing %s", msg, input)
-								}
-							}
-							data := bytes.Join(s, []byte(t.Join.Separator))
-							if err := b.Opts.Store.Set(string(t.Output), data); err != nil {
-								return errors.Format("%s: %w", msg, err)
-							}
-							log.Debug("set artifact: " + string(t.Output))
-						default:
-							return errors.Format("%s: unsupported kind %s", msg, t.Kind)
-						}
-					}
-
-					// Write the final artifact
-					if err := b.Opts.Store.Save(b.Opts.WriteTo, string(a.Artifact)); err != nil {
-						return errors.Format("%s: %w", msg, err)
-					}
-					log.DebugContext(ctx, "wrote "+filepath.Join(b.Opts.WriteTo, string(a.Artifact)))
-
-					return nil
-				})
-			}
+func (t generatorTask) run(ctx context.Context) error {
+	defer t.wg.Done()
+	msg := fmt.Sprintf("could not build %s", t.id())
+	switch t.generator.Kind {
+	case "Resources":
+		if err := t.resources(); err != nil {
+			return errors.Format("%s: could not generate resources: %w", msg, err)
 		}
-		return nil
-	})
-
-	// Wait for completion and return the first error (if any)
-	return g.Wait()
-}
-
-func (b *BuildPlan) Export(idx int, encoder holos.OrderedEncoder) error {
-	if err := encoder.Encode(idx, &b.BuildPlan); err != nil {
-		return errors.Wrap(err)
+	case "Helm":
+		if err := t.helm(ctx); err != nil {
+			return errors.Format("%s: could not generate helm: %w", msg, err)
+		}
+	case "File":
+		if err := t.file(); err != nil {
+			return errors.Format("%s: could not generate file: %w", msg, err)
+		}
+	default:
+		return errors.Format("%s: unsupported kind %s", msg, t.generator.Kind)
 	}
 	return nil
 }
 
-func (b *BuildPlan) Load(v cue.Value) error {
-	return errors.Wrap(v.Decode(&b.BuildPlan))
-}
-
-func (b *BuildPlan) file(
-	log *slog.Logger,
-	g core.Generator,
-	store artifact.Store,
-) error {
-	data, err := os.ReadFile(filepath.Join(string(b.Opts.Path), string(g.File.Source)))
+func (t generatorTask) file() error {
+	data, err := os.ReadFile(filepath.Join(string(t.opts.Path), string(t.generator.File.Source)))
 	if err != nil {
 		return errors.Wrap(err)
 	}
-	if err := store.Set(string(g.Output), data); err != nil {
+	if err := t.opts.Store.Set(string(t.generator.Output), data); err != nil {
 		return errors.Wrap(err)
 	}
-	log.Debug("set artifact: " + string(g.Output))
 	return nil
 }
 
-func (b *BuildPlan) helm(
-	ctx context.Context,
-	log *slog.Logger,
-	g core.Generator,
-	store artifact.Store,
-) error {
-	chartName := g.Helm.Chart.Name
-	log = log.With("chart", chartName)
+func (t generatorTask) helm(ctx context.Context) error {
+	chartName := t.generator.Helm.Chart.Name
 	// Unnecessary? cargo cult copied from internal/cli/render/render.go
 	if chartName == "" {
 		return errors.New("missing chart name")
 	}
-
 	// Cache the chart by version to pull new versions. (#273)
-	cacheDir := filepath.Join(string(b.Opts.Path), "vendor", g.Helm.Chart.Version)
+	cacheDir := filepath.Join(string(t.opts.Path), "vendor", t.generator.Helm.Chart.Version)
 	cachePath := filepath.Join(cacheDir, filepath.Base(chartName))
 
+	log := logger.FromContext(ctx)
+
 	if _, err := os.Stat(cachePath); os.IsNotExist(err) {
-		timeout, cancel := context.WithTimeout(ctx, 5*time.Minute)
-		defer cancel()
-		err := onceWithLock(log, timeout, cachePath, func() error {
-			return b.cacheChart(ctx, log, cacheDir, g.Helm.Chart)
-		})
+		err := func() error {
+			ctx, cancel := context.WithTimeout(ctx, 5*time.Minute)
+			defer cancel()
+			return onceWithLock(log, ctx, cachePath, func() error {
+				return cacheChart(ctx, cacheDir, t.generator.Helm.Chart, t.opts.Stderr)
+			})
+		}()
 		if err != nil {
 			return errors.Format("could not cache chart: %w", err)
 		}
@@ -269,7 +198,7 @@ func (b *BuildPlan) helm(
 	}
 	defer util.Remove(ctx, tempDir)
 
-	data, err := yaml.Marshal(g.Helm.Values)
+	data, err := yaml.Marshal(t.generator.Helm.Values)
 	if err != nil {
 		return errors.Format("could not marshal values: %w", err)
 	}
@@ -282,22 +211,22 @@ func (b *BuildPlan) helm(
 
 	// Run charts
 	args := []string{"template"}
-	if !g.Helm.EnableHooks {
+	if !t.generator.Helm.EnableHooks {
 		args = append(args, "--no-hooks")
 	}
-	for _, apiVersion := range g.Helm.APIVersions {
+	for _, apiVersion := range t.generator.Helm.APIVersions {
 		args = append(args, "--api-versions", apiVersion)
 	}
-	if kubeVersion := g.Helm.KubeVersion; kubeVersion != "" {
+	if kubeVersion := t.generator.Helm.KubeVersion; kubeVersion != "" {
 		args = append(args, "--kube-version", kubeVersion)
 	}
 	args = append(args,
 		"--include-crds",
 		"--values", valuesPath,
-		"--namespace", g.Helm.Namespace,
+		"--namespace", t.generator.Helm.Namespace,
 		"--kubeconfig", "/dev/null",
-		"--version", g.Helm.Chart.Version,
-		g.Helm.Chart.Release,
+		"--version", t.generator.Helm.Chart.Version,
+		t.generator.Helm.Chart.Release,
 		cachePath,
 	)
 	helmOut, err := util.RunCmd(ctx, "helm", args...)
@@ -314,36 +243,31 @@ func (b *BuildPlan) helm(
 	}
 
 	// Set the artifact
-	if err := store.Set(string(g.Output), helmOut.Stdout.Bytes()); err != nil {
+	if err := t.opts.Store.Set(string(t.generator.Output), helmOut.Stdout.Bytes()); err != nil {
 		return errors.Format("could not store helm output: %w", err)
 	}
-	log.Debug("set artifact: " + string(g.Output))
+	log.Debug("set artifact: " + string(t.generator.Output))
 
 	return nil
 }
 
-func (b *BuildPlan) resources(
-	log *slog.Logger,
-	g core.Generator,
-	store artifact.Store,
-) error {
+func (t generatorTask) resources() error {
 	var size int
-	for _, m := range g.Resources {
+	for _, m := range t.generator.Resources {
 		size += len(m)
 	}
 	list := make([]core.Resource, 0, size)
 
-	for _, m := range g.Resources {
+	for _, m := range t.generator.Resources {
 		for _, r := range m {
 			list = append(list, r)
 		}
 	}
 
 	msg := fmt.Sprintf(
-		"could not generate %s for %s path %s",
-		g.Output,
-		b.BuildPlan.Metadata.Name,
-		b.Opts.Path,
+		"could not generate %s for %s",
+		t.generator.Output,
+		t.id(),
 	)
 
 	buf, err := marshal(list)
@@ -351,70 +275,220 @@ func (b *BuildPlan) resources(
 		return errors.Format("%s: %w", msg, err)
 	}
 
-	if err := store.Set(string(g.Output), buf.Bytes()); err != nil {
+	if err := t.opts.Store.Set(string(t.generator.Output), buf.Bytes()); err != nil {
 		return errors.Format("%s: %w", msg, err)
 	}
 
-	log.Debug("set artifact " + string(g.Output))
 	return nil
 }
 
-func (b *BuildPlan) kustomize(
-	ctx context.Context,
-	log *slog.Logger,
-	t core.Transformer,
-	store artifact.Store,
-) error {
-	tempDir, err := os.MkdirTemp("", "holos.kustomize")
-	if err != nil {
-		return errors.Wrap(err)
-	}
-	defer util.Remove(ctx, tempDir)
-	msg := fmt.Sprintf(
-		"could not transform %s for %s path %s",
-		t.Output,
-		b.BuildPlan.Metadata.Name,
-		b.Opts.Path,
-	)
+type transformersTask struct {
+	taskParams
+	transformers []core.Transformer
+	wg           *sync.WaitGroup
+}
 
-	// Write the kustomization
-	data, err := yaml.Marshal(t.Kustomize.Kustomization)
-	if err != nil {
-		return errors.Format("%s: %w", msg, err)
-	}
-	path := filepath.Join(tempDir, "kustomization.yaml")
-	if err := os.WriteFile(path, data, 0666); err != nil {
-		return errors.Format("%s: %w", msg, err)
-	}
-	log.DebugContext(ctx, "wrote "+path)
-
-	// Write the inputs
-	for _, input := range t.Inputs {
-		path := string(input)
-		if err := store.Save(tempDir, path); err != nil {
-			return errors.Format("%s: %w", msg, err)
+func (t transformersTask) run(ctx context.Context) error {
+	defer t.wg.Done()
+	for idx, transformer := range t.transformers {
+		msg := fmt.Sprintf("could not build %s/%d", t.id(), idx)
+		switch transformer.Kind {
+		case "Kustomize":
+			if err := kustomize(ctx, transformer, t.taskParams); err != nil {
+				return errors.Wrap(err)
+			}
+		case "Join":
+			s := make([][]byte, 0, len(transformer.Inputs))
+			for _, input := range transformer.Inputs {
+				if data, ok := t.opts.Store.Get(string(input)); ok {
+					s = append(s, data)
+				} else {
+					return errors.Format("%s: missing %s", msg, input)
+				}
+			}
+			data := bytes.Join(s, []byte(transformer.Join.Separator))
+			if err := t.opts.Store.Set(string(transformer.Output), data); err != nil {
+				return errors.Format("%s: %w", msg, err)
+			}
+		default:
+			return errors.Format("%s: unsupported kind %s", msg, transformer.Kind)
 		}
-		log.DebugContext(ctx, "wrote "+filepath.Join(tempDir, path))
 	}
+	return nil
+}
 
-	// Execute kustomize
-	r, err := util.RunCmd(ctx, "kubectl", "kustomize", tempDir)
-	if err != nil {
-		kErr := r.Stderr.String()
-		err = errors.Format("%s: could not run kustomize: %w", msg, err)
-		log.ErrorContext(ctx, fmt.Sprintf("%s: stderr:\n%s", err.Error(), kErr), "err", err, "stderr", kErr)
-		return err
+type validatorTask struct {
+	taskParams
+	validator core.Validator
+	wg        *sync.WaitGroup
+}
+
+func (t validatorTask) run(ctx context.Context) error {
+	defer t.wg.Done()
+	msg := fmt.Sprintf("could not validate %s", t.id())
+	switch kind := t.validator.Kind; kind {
+	case "Command":
+		if err := validate(ctx, t.validator, t.taskParams); err != nil {
+			return errors.Wrap(err)
+		}
+	default:
+		return errors.Format("%s: unsupported kind %s", msg, kind)
 	}
+	return nil
+}
 
-	// Store the artifact
-	if err := store.Set(string(t.Output), r.Stdout.Bytes()); err != nil {
+func worker(ctx context.Context, idx int, tasks chan task) error {
+	log := logger.FromContext(ctx).With("worker", idx)
+	for {
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		case task, ok := <-tasks:
+			if !ok {
+				log.DebugContext(ctx, fmt.Sprintf("worker %d returning: tasks chan closed", idx))
+				return nil
+			}
+			log.DebugContext(ctx, fmt.Sprintf("worker %d task %s starting", idx, task.id()))
+			if err := task.run(ctx); err != nil {
+				return errors.Wrap(err)
+			}
+			log.DebugContext(ctx, fmt.Sprintf("worker %d task %s finished ok", idx, task.id()))
+		}
+	}
+}
+
+func buildArtifact(ctx context.Context, idx int, artifact core.Artifact, tasks chan task, buildPlanName string, opts holos.BuildOpts) error {
+	var wg sync.WaitGroup
+	msg := fmt.Sprintf("could not build %s artifact %s", buildPlanName, artifact.Artifact)
+	// Process Generators concurrently
+	for gid, gen := range artifact.Generators {
+		task := generatorTask{
+			taskParams: taskParams{
+				taskName:      fmt.Sprintf("artifact/%d/generator/%d", idx, gid),
+				buildPlanName: buildPlanName,
+				opts:          opts,
+			},
+			generator: gen,
+			wg:        &wg,
+		}
+		wg.Add(1)
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		case tasks <- task:
+		}
+	}
+	wg.Wait()
+
+	// Process Transformers sequentially
+	task := transformersTask{
+		taskParams: taskParams{
+			taskName:      fmt.Sprintf("artifact/%d/transformers", idx),
+			buildPlanName: buildPlanName,
+			opts:          opts,
+		},
+		transformers: artifact.Transformers,
+		wg:           &wg,
+	}
+	wg.Add(1)
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	case tasks <- task:
+	}
+	wg.Wait()
+
+	// Process Validators concurrently
+	for vid, val := range artifact.Validators {
+		task := validatorTask{
+			taskParams: taskParams{
+				taskName:      fmt.Sprintf("artifact/%d/validator/%d", idx, vid),
+				buildPlanName: buildPlanName,
+				opts:          opts,
+			},
+			validator: val,
+			wg:        &wg,
+		}
+		wg.Add(1)
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		case tasks <- task:
+		}
+	}
+	wg.Wait()
+
+	// Write the final artifact
+	out := string(artifact.Artifact)
+	if err := opts.Store.Save(opts.WriteTo, out); err != nil {
 		return errors.Format("%s: %w", msg, err)
 	}
-	log.Debug("set artifact " + string(t.Output))
+	log := logger.FromContext(ctx)
+	log.DebugContext(ctx, fmt.Sprintf("wrote %s", filepath.Join(opts.WriteTo, out)))
 
 	return nil
 }
 
+// BuildPlan represents a component builder.
+type BuildPlan struct {
+	core.BuildPlan
+	Opts holos.BuildOpts
+}
+
+func (b *BuildPlan) Build(ctx context.Context) error {
+	name := b.BuildPlan.Metadata.Name
+	path := b.Opts.Path
+	log := logger.FromContext(ctx).With("name", name, "path", path)
+
+	msg := fmt.Sprintf("could not build %s", name)
+	if b.BuildPlan.Spec.Disabled {
+		log.WarnContext(ctx, fmt.Sprintf("%s: disabled", msg))
+		return nil
+	}
+
+	g, ctx := errgroup.WithContext(ctx)
+	tasks := make(chan task)
+
+	// Start the worker pool.
+	for idx := 0; idx < max(1, b.Opts.Concurrency); idx++ {
+		g.Go(func() error {
+			return worker(ctx, idx, tasks)
+		})
+	}
+
+	// Start one producer that fans out to one pipeline per artifact.
+	g.Go(func() error {
+		// Close the tasks chan when the producer returns.
+		defer func() {
+			log.DebugContext(ctx, "producer returning: closing tasks chan")
+			close(tasks)
+		}()
+		// Separate error group for producers.
+		p, ctx := errgroup.WithContext(ctx)
+		for idx, a := range b.BuildPlan.Spec.Artifacts {
+			p.Go(func() error {
+				return buildArtifact(ctx, idx, a, tasks, b.Metadata.Name, b.Opts)
+			})
+		}
+		// Wait on producers to finish.
+		return errors.Wrap(p.Wait())
+	})
+
+	// Wait on workers to finish.
+	return g.Wait()
+}
+
+func (b *BuildPlan) Export(idx int, encoder holos.OrderedEncoder) error {
+	if err := encoder.Encode(idx, &b.BuildPlan); err != nil {
+		return errors.Wrap(err)
+	}
+	return nil
+}
+
+func (b *BuildPlan) Load(v cue.Value) error {
+	return errors.Wrap(v.Decode(&b.BuildPlan))
+}
+
 func marshal(list []core.Resource) (buf bytes.Buffer, err error) {
 	encoder := yaml.NewEncoder(&buf)
 	defer encoder.Close()
@@ -427,27 +501,59 @@ func marshal(list []core.Resource) (buf bytes.Buffer, err error) {
 	return
 }
 
-// cacheChart stores a cached copy of Chart in the chart subdirectory of path.
-//
-// We assume the only method responsible for writing to chartDir is cacheChart
-// itself.  cacheChart runs concurrently when rendering a platform.
-//
-// We rely on the atomicity of moving temporary directories into place on the
-// same filesystem via os.Rename. If a syscall.EEXIST error occurs during
-// renaming, it indicates that the cached chart already exists, which is
-// expected when this function is called concurrently.
-//
-// TODO(jeff): Break the dependency on v1alpha5, make it work across versions as
-// a utility function.
-func (b *BuildPlan) cacheChart(
-	ctx context.Context,
-	log *slog.Logger,
-	cacheDir string,
-	chart core.Chart,
-) error {
+// onceWithLock obtains a filesystem lock with mkdir, then executes fn.  If the
+// lock is already locked, onceWithLock waits for it to be released then returns
+// without calling fn.
+func onceWithLock(log *slog.Logger, ctx context.Context, path string, fn func() error) error {
+	if err := os.MkdirAll(filepath.Dir(path), 0777); err != nil {
+		return errors.Wrap(err)
+	}
+
+	// Obtain a lock with a timeout.
+	lockDir := path + ".lock"
+	log = log.With("lock", lockDir)
+
+	err := os.Mkdir(lockDir, 0777)
+	if err == nil {
+		defer os.RemoveAll(lockDir)
+		log.DebugContext(ctx, fmt.Sprintf("acquired %s", lockDir))
+		if err := fn(); err != nil {
+			return errors.Wrap(err)
+		}
+		log.DebugContext(ctx, fmt.Sprintf("released %s", lockDir))
+		return nil
+	}
+
+	// Wait until the lock is released then return.
+	if os.IsExist(err) {
+		log.DebugContext(ctx, fmt.Sprintf("blocked %s", lockDir))
+		stillBlocked := time.After(5 * time.Second)
+		deadLocked := time.After(10 * time.Second)
+		for {
+			select {
+			case <-stillBlocked:
+				log.WarnContext(ctx, fmt.Sprintf("waiting for %s to be released", lockDir))
+			case <-deadLocked:
+				log.WarnContext(ctx, fmt.Sprintf("still waiting for %s to be released (dead lock?)", lockDir))
+			case <-time.After(100 * time.Millisecond):
+				if _, err := os.Stat(lockDir); os.IsNotExist(err) {
+					log.DebugContext(ctx, fmt.Sprintf("unblocked %s", lockDir))
+					return nil
+				}
+			case <-ctx.Done():
+				return errors.Wrap(ctx.Err())
+			}
+		}
+	}
+
+	// Unexpected error
+	return errors.Wrap(err)
+}
+
+func cacheChart(ctx context.Context, cacheDir string, chart core.Chart, stderr io.Writer) error {
+	log := logger.FromContext(ctx)
 	// Add repositories
 	repo := chart.Repository
-	stderr := b.Opts.Stderr
 	if repo.URL == "" {
 		// repo update not needed for oci charts so this is debug instead of warn.
 		log.DebugContext(ctx, "skipped helm repo add and update: repo url is empty")
@@ -516,51 +622,82 @@ func (b *BuildPlan) cacheChart(
 	return nil
 }
 
-// onceWithLock obtains a filesystem lock with mkdir, then executes fn.  If the
-// lock is already locked, onceWithLock waits for it to be released then returns
-// without calling fn.
-func onceWithLock(log *slog.Logger, ctx context.Context, path string, fn func() error) error {
-	if err := os.MkdirAll(filepath.Dir(path), 0777); err != nil {
+func kustomize(ctx context.Context, t core.Transformer, p taskParams) error {
+	tempDir, err := os.MkdirTemp("", "holos.kustomize")
+	if err != nil {
 		return errors.Wrap(err)
 	}
+	defer util.Remove(ctx, tempDir)
+	msg := fmt.Sprintf(
+		"could not transform %s for %s path %s",
+		t.Output,
+		p.buildPlanName,
+		p.opts.Path,
+	)
 
-	// Obtain a lock with a timeout.
-	lockDir := path + ".lock"
-	log = log.With("lock", lockDir)
-
-	err := os.Mkdir(lockDir, 0777)
-	if err == nil {
-		defer os.RemoveAll(lockDir)
-		log.DebugContext(ctx, fmt.Sprintf("acquired %s", lockDir))
-		if err := fn(); err != nil {
-			return errors.Wrap(err)
-		}
-		log.DebugContext(ctx, fmt.Sprintf("released %s", lockDir))
-		return nil
+	// Write the kustomization
+	data, err := yaml.Marshal(t.Kustomize.Kustomization)
+	if err != nil {
+		return errors.Format("%s: %w", msg, err)
+	}
+	path := filepath.Join(tempDir, "kustomization.yaml")
+	if err := os.WriteFile(path, data, 0666); err != nil {
+		return errors.Format("%s: %w", msg, err)
 	}
 
-	// Wait until the lock is released then return.
-	if os.IsExist(err) {
-		log.DebugContext(ctx, fmt.Sprintf("blocked %s", lockDir))
-		stillBlocked := time.After(5 * time.Second)
-		deadLocked := time.After(10 * time.Second)
-		for {
-			select {
-			case <-stillBlocked:
-				log.WarnContext(ctx, fmt.Sprintf("waiting for %s to be released", lockDir))
-			case <-deadLocked:
-				log.WarnContext(ctx, fmt.Sprintf("still waiting for %s to be released (dead lock?)", lockDir))
-			case <-time.After(100 * time.Millisecond):
-				if _, err := os.Stat(lockDir); os.IsNotExist(err) {
-					log.DebugContext(ctx, fmt.Sprintf("unblocked %s", lockDir))
-					return nil
-				}
-			case <-ctx.Done():
-				return errors.Wrap(ctx.Err())
-			}
+	// Write the inputs
+	for _, input := range t.Inputs {
+		path := string(input)
+		if err := p.opts.Store.Save(tempDir, path); err != nil {
+			return errors.Format("%s: %w", msg, err)
 		}
 	}
 
-	// Unexpected error
-	return errors.Wrap(err)
+	// Execute kustomize
+	r, err := util.RunCmdW(ctx, p.opts.Stderr, "kubectl", "kustomize", tempDir)
+	if err != nil {
+		return errors.Format("%s: could not run kustomize: %w", msg, err)
+	}
+
+	// Store the artifact
+	if err := p.opts.Store.Set(string(t.Output), r.Stdout.Bytes()); err != nil {
+		return errors.Format("%s: %w", msg, err)
+	}
+
+	return nil
+}
+
+func validate(ctx context.Context, validator core.Validator, p taskParams) error {
+	store := p.opts.Store
+	tempDir, err := os.MkdirTemp("", "holos.validate")
+	if err != nil {
+		return errors.Wrap(err)
+	}
+	// defer util.Remove(ctx, tempDir)
+	msg := fmt.Sprintf("could not validate %s", p.id())
+
+	// Write the inputs
+	for _, input := range validator.Inputs {
+		path := string(input)
+		if err := store.Save(tempDir, path); err != nil {
+			return errors.Format("%s: %w", msg, err)
+		}
+	}
+
+	if len(validator.Command.Args) < 1 {
+		return errors.Format("%s: command args length must be at least 1", msg)
+	}
+	size := len(validator.Command.Args) + len(validator.Inputs)
+	args := make([]string, 0, size)
+	args = append(args, validator.Command.Args...)
+	for _, input := range validator.Inputs {
+		args = append(args, filepath.Join(tempDir, string(input)))
+	}
+
+	// Execute the validator
+	if _, err = util.RunCmdA(ctx, p.opts.Stderr, args[0], args[1:]...); err != nil {
+		return errors.Format("%s: %w", msg, err)
+	}
+
+	return nil
 }

internal/cli/main.go

@@ -4,6 +4,9 @@ import (
 	"context"
 	"fmt"
 	"log/slog"
+	"os"
+	"runtime/pprof"
+	"runtime/trace"
 
 	"connectrpc.com/connect"
 	cue "cuelang.org/go/cue/errors"
@@ -12,12 +15,48 @@ import (
 	"google.golang.org/genproto/googleapis/rpc/errdetails"
 )
 
+func memProfile(ctx context.Context, cfg *holos.Config) {
+	if format := os.Getenv("HOLOS_MEM_PROFILE"); format != "" {
+		f, _ := os.Create(fmt.Sprintf(format, os.Getppid(), os.Getpid()))
+		defer f.Close()
+		if err := pprof.WriteHeapProfile(f); err != nil {
+			_ = HandleError(ctx, err, cfg)
+		}
+	}
+}
+
 // MakeMain makes a main function for the cli or tests.
 func MakeMain(options ...holos.Option) func() int {
 	return func() (exitCode int) {
 		cfg := holos.New(options...)
 		slog.SetDefault(cfg.Logger())
 		ctx := context.Background()
+
+		if format := os.Getenv("HOLOS_CPU_PROFILE"); format != "" {
+			f, _ := os.Create(fmt.Sprintf(format, os.Getppid(), os.Getpid()))
+			err := pprof.StartCPUProfile(f)
+			defer func() {
+				pprof.StopCPUProfile()
+				f.Close()
+			}()
+			if err != nil {
+				return HandleError(ctx, err, cfg)
+			}
+		}
+		defer memProfile(ctx, cfg)
+
+		if format := os.Getenv("HOLOS_TRACE"); format != "" {
+			f, _ := os.Create(fmt.Sprintf(format, os.Getppid(), os.Getpid()))
+			err := trace.Start(f)
+			defer func() {
+				trace.Stop()
+				f.Close()
+			}()
+			if err != nil {
+				return HandleError(ctx, err, cfg)
+			}
+		}
+
 		feature := &holos.EnvFlagger{}
 		if err := New(cfg, feature).ExecuteContext(ctx); err != nil {
 			return HandleError(ctx, err, cfg)

internal/cli/render/render.go

@@ -16,6 +16,8 @@ import (
 	"github.com/spf13/cobra"
 )
 
+const tagHelp = "set the value of a cue @tag field in the form key [ = value ]"
+
 func New(cfg *holos.Config, feature holos.Flagger) *cobra.Command {
 	cmd := command.New("render")
 	cmd.Args = cobra.NoArgs
@@ -26,7 +28,7 @@ func New(cfg *holos.Config, feature holos.Flagger) *cobra.Command {
 }
 
 func newPlatform(cfg *holos.Config, feature holos.Flagger) *cobra.Command {
-	cmd := command.New("platform DIRECTORY")
+	cmd := command.New("platform")
 	cmd.Args = cobra.MaximumNArgs(1)
 	cmd.Example = "holos render platform"
 	cmd.Short = "render an entire platform"
@@ -38,13 +40,13 @@ func newPlatform(cfg *holos.Config, feature holos.Flagger) *cobra.Command {
 	}
 
 	var concurrency int
-	cmd.Flags().IntVar(&concurrency, "concurrency", min(runtime.NumCPU(), 8), "number of components to render concurrently")
+	cmd.Flags().IntVar(&concurrency, "concurrency", runtime.NumCPU(), "number of components to render concurrently")
 	var platform string
 	cmd.Flags().StringVar(&platform, "platform", "./platform", "platform directory path")
 	var selector holos.Selector
 	cmd.Flags().VarP(&selector, "selector", "l", "label selector (e.g. label==string,label!=string)")
 	tagMap := make(holos.TagMap)
-	cmd.Flags().VarP(&tagMap, "inject", "t", "set the value of a cue @tag field from a key=value pair")
+	cmd.Flags().VarP(&tagMap, "inject", "t", tagHelp)
 
 	cmd.RunE = func(cmd *cobra.Command, args []string) error {
 		ctx := cmd.Root().Context()
@@ -70,7 +72,7 @@ func newPlatform(cfg *holos.Config, feature holos.Flagger) *cobra.Command {
 			"--log-format", cfg.LogConfig().Format(),
 		}
 		opts := builder.PlatformOpts{
-			Fn:          makePlatformRenderFunc(cmd.ErrOrStderr(), prefixArgs),
+			Fn:          makeComponentRenderFunc(cmd.ErrOrStderr(), prefixArgs, tagMap.Tags()),
 			Selector:    selector,
 			Concurrency: concurrency,
 			InfoEnabled: true,
@@ -102,9 +104,9 @@ func newComponent(cfg *holos.Config, feature holos.Flagger) *cobra.Command {
 	}
 
 	tagMap := make(holos.TagMap)
-	cmd.Flags().VarP(&tagMap, "inject", "t", "set the value of a cue @tag field from a key=value pair")
+	cmd.Flags().VarP(&tagMap, "inject", "t", tagHelp)
 	var concurrency int
-	cmd.Flags().IntVar(&concurrency, "concurrency", min(runtime.NumCPU(), 8), "number of concurrent build steps")
+	cmd.Flags().IntVar(&concurrency, "concurrency", runtime.NumCPU(), "number of concurrent build steps")
 
 	cmd.RunE = func(cmd *cobra.Command, args []string) error {
 		ctx := cmd.Root().Context()
@@ -134,7 +136,7 @@ func newComponent(cfg *holos.Config, feature holos.Flagger) *cobra.Command {
 	return cmd
 }
 
-func makePlatformRenderFunc(w io.Writer, prefixArgs []string) builder.BuildFunc {
+func makeComponentRenderFunc(w io.Writer, prefixArgs, cliTags []string) func(context.Context, int, holos.Component) error {
 	return func(ctx context.Context, idx int, component holos.Component) error {
 		select {
 		case <-ctx.Done():
@@ -147,11 +149,14 @@ func makePlatformRenderFunc(w io.Writer, prefixArgs []string) builder.BuildFunc
 			args := make([]string, 0, 10+len(prefixArgs)+(len(tags)*2))
 			args = append(args, prefixArgs...)
 			args = append(args, "render", "component")
+			for _, tag := range cliTags {
+				args = append(args, "--inject", tag)
+			}
 			for _, tag := range tags {
 				args = append(args, "--inject", tag)
 			}
 			args = append(args, component.Path())
-			if _, err := util.RunCmdW(ctx, w, "holos", args...); err != nil {
+			if _, err := util.RunCmdA(ctx, w, "holos", args...); err != nil {
 				return errors.Format("could not render component: %w", err)
 			}
 		}

internal/cli/root.go

@@ -4,7 +4,6 @@ import (
 	_ "embed"
 	"fmt"
 	"log/slog"
-	"os"
 
 	"github.com/spf13/cobra"
 
@@ -119,7 +118,20 @@ func newOrgCmd(feature holos.Flagger) (cmd *cobra.Command) {
 }
 
 func newCueCmd() (cmd *cobra.Command) {
-	cueCmd, _ := cue.New(os.Args[1:])
-	cmd = cueCmd.Command
-	return
+	// Get a handle on the cue root command fields.
+	root, _ := cue.New([]string{})
+	// Copy the fields to our embedded command.
+	cmd = command.New("cue")
+	cmd.Short = root.Short
+	cmd.Long = root.Long
+	// Pass all arguments through to RunE.
+	cmd.DisableFlagParsing = true
+	cmd.Args = cobra.ArbitraryArgs
+
+	// We do it this way so we handle errors correctly.
+	cmd.RunE = func(cmd *cobra.Command, args []string) error {
+		cueRootCommand, _ := cue.New(args)
+		return cueRootCommand.Run(cmd.Root().Context())
+	}
+	return cmd
 }

internal/cli/show.go

@@ -94,6 +94,7 @@ func newShowBuildPlanCmd() (cmd *cobra.Command) {
 		buildPlanOpts := holos.NewBuildOpts(path)
 		buildPlanOpts.Stderr = cmd.ErrOrStderr()
 		buildPlanOpts.Concurrency = concurrency
+		buildPlanOpts.Tags = tagMap.Tags()
 
 		platformOpts := builder.PlatformOpts{
 			Fn:          makeBuildFunc(encoder, buildPlanOpts),
@@ -110,7 +111,7 @@ func newShowBuildPlanCmd() (cmd *cobra.Command) {
 	return cmd
 }
 
-func makeBuildFunc(encoder holos.OrderedEncoder, opts holos.BuildOpts) builder.BuildFunc {
+func makeBuildFunc(encoder holos.OrderedEncoder, opts holos.BuildOpts) func(context.Context, int, holos.Component) error {
 	return func(ctx context.Context, idx int, component holos.Component) error {
 		select {
 		case <-ctx.Done():
@@ -120,6 +121,7 @@ func makeBuildFunc(encoder holos.OrderedEncoder, opts holos.BuildOpts) builder.B
 			if err != nil {
 				return errors.Wrap(err)
 			}
+			tags = append(tags, opts.Tags...)
 			inst, err := builder.LoadInstance(component.Path(), tags)
 			if err != nil {
 				return errors.Wrap(err)

internal/generate/platforms/cue.mod/gen/github.com/holos-run/holos/api/author/v1alpha5/definitions_go_gen.cue

@@ -72,9 +72,12 @@ import "github.com/holos-run/holos/api/core/v1alpha5:core"
 	// Resources represents kubernetes resources mixed into the rendered manifest.
 	Resources: core.#Resources
 
-	// KustomizeConfig represents the configuration kustomize.
+	// KustomizeConfig represents the kustomize configuration.
 	KustomizeConfig: #KustomizeConfig
 
+	// Validators represent checks that must pass for output to be written.
+	Validators: {[string]: core.#Validator} @go(,map[NameLabel]core.Validator)
+
 	// Artifacts represents additional artifacts to mix in.  Useful for adding
 	// GitOps resources.  Each Artifact is unified without modification into the
 	// BuildPlan.

internal/generate/platforms/cue.mod/gen/github.com/holos-run/holos/api/core/v1alpha5/types_go_gen.cue

@@ -46,14 +46,6 @@ package core
 	disabled?: bool @go(Disabled)
 }
 
-// BuildPlanSource reflects the origin of a [BuildPlan].  Useful to save a build
-// plan to a file, then re-generate it without needing to process a [Platform]
-// component collection.
-#BuildPlanSource: {
-	// Component reflects the component that produced the build plan.
-	component?: #Component @go(Component)
-}
-
 // Artifact represents one fully rendered manifest produced by a [Transformer]
 // sequence, which transforms a [Generator] collection.  A [BuildPlan] produces
 // an [Artifact] collection.
@@ -78,6 +70,7 @@ package core
 	artifact?: #FilePath @go(Artifact)
 	generators?: [...#Generator] @go(Generators,[]Generator)
 	transformers?: [...#Transformer] @go(Transformers,[]Transformer)
+	validators?: [...#Validator] @go(Validators,[]Validator)
 	skip?: bool @go(Skip)
 }
 
@@ -229,15 +222,39 @@ package core
 // is expected to happen in CUE against the kubectl version the user prefers.
 #Kustomization: {...}
 
-// FileContent represents file contents.
-#FileContent: string
-
 // FileContentMap represents a mapping of file paths to file contents.
 #FileContentMap: {[string]: #FileContent}
 
 // FilePath represents a file path.
 #FilePath: string
 
+// FileContent represents file contents.
+#FileContent: string
+
+// Validator validates files.  Useful to validate an [Artifact] prior to writing
+// it out to the final destination.  Holos may execute validators concurrently.
+// See the [validators] tutorial for an end to end example.
+//
+// [validators]: https://holos.run/docs/v1alpha5/tutorial/validators/
+#Validator: {
+	// Kind represents the kind of transformer. Must be Kustomize, or Join.
+	kind: string & "Command" @go(Kind)
+
+	// Inputs represents the files to validate.  Usually the final Artifact.
+	inputs: [...#FilePath] @go(Inputs,[]FilePath)
+
+	// Command represents a validation command.  Ignored unless kind is Command.
+	command?: #Command @go(Command)
+}
+
+// Command represents a command vetting one or more artifacts.  Holos appends
+// fully qualified input file paths to the end of the args list, then executes
+// the command.  Inputs are written into a temporary directory prior to
+// executing the command and removed afterwards.
+#Command: {
+	args?: [...string] @go(Args,[]string)
+}
+
 // InternalLabel is an arbitrary unique identifier internal to holos itself.
 // The holos cli is expected to never write a InternalLabel value to rendered
 // output files, therefore use a InternalLabel when the identifier must be

internal/generate/platforms/cue.mod/pkg/github.com/holos-run/holos/api/author/v1alpha5/definitions.cue

@@ -19,11 +19,14 @@ import (
 	Kustomization: ks.#Kustomization & {
 		apiVersion: "kustomize.config.k8s.io/v1beta1"
 		kind:       "Kustomization"
-		_labels: commonLabels: {
-			includeSelectors: false
-			pairs:            CommonLabels
+		_labels: {}
+		if len(CommonLabels) > 0 {
+			_labels: commonLabels: {
+				includeSelectors: false
+				pairs:            CommonLabels
+			}
+			labels: [for x in _labels {x}]
 		}
-		labels: [for x in _labels {x}]
 	}
 }
 
@@ -40,20 +43,11 @@ import (
 	Path:            _
 	Parameters:      _
 	Resources:       _
-	OutputBaseDir:   _
 	KustomizeConfig: _
 
 	Artifacts: {
 		HolosComponent: {
-			_path: string
-			if OutputBaseDir == "" {
-				_path: "components/\(Name)"
-			}
-			if OutputBaseDir != "" {
-				_path: "\(OutputBaseDir)/components/\(Name)"
-			}
-
-			artifact: "\(_path)/\(Name).gen.yaml"
+			artifact: _
 			let ResourcesOutput = "resources.gen.yaml"
 			generators: [
 				{
@@ -83,17 +77,6 @@ import (
 			]
 		}
 	}
-
-	BuildPlan: {
-		metadata: name: Name
-		if len(Labels) != 0 {
-			metadata: labels: Labels
-		}
-		if len(Annotations) != 0 {
-			metadata: annotations: Annotations
-		}
-		spec: artifacts: [for x in Artifacts {x}]
-	}
 }
 
 // https://holos.run/docs/next/api/author/#Helm
@@ -119,15 +102,7 @@ import (
 
 	Artifacts: {
 		HolosComponent: {
-			_path: string
-			if OutputBaseDir == "" {
-				_path: "components/\(Name)"
-			}
-			if OutputBaseDir != "" {
-				_path: "\(OutputBaseDir)/components/\(Name)"
-			}
-
-			artifact: "\(_path)/\(Name).gen.yaml"
+			artifact: _
 			let HelmOutput = "helm.gen.yaml"
 			let ResourcesOutput = "resources.gen.yaml"
 			generators: [
@@ -177,6 +152,26 @@ import (
 			]
 		}
 	}
+}
+
+#ComponentConfig: {
+	Name:          _
+	Labels:        _
+	Annotations:   _
+	Validators:    _
+	OutputBaseDir: _
+
+	Artifacts: HolosComponent: {
+		_path: string
+		if OutputBaseDir == "" {
+			_path: "components/\(Name)"
+		}
+		if OutputBaseDir != "" {
+			_path: "\(OutputBaseDir)/components/\(Name)"
+		}
+		artifact: "\(_path)/\(Name).gen.yaml"
+		validators: [for x in Validators {x & {inputs: [artifact]}}]
+	}
 
 	BuildPlan: {
 		metadata: name: Name

internal/generate/platforms/cue.mod/pkg/sigs.k8s.io/kustomize/api/types/var.cue

@@ -0,0 +1,7 @@
+package types
+
+#Target: {
+	// Ensure name has a concrete value so json.Marshal works.  See
+	// https://github.com/holos-run/holos/issues/348
+	name: string | *""
+}

internal/holos/types.go

@@ -14,12 +14,10 @@ import (
 	"gopkg.in/yaml.v3"
 )
 
-// yamlEncoder and jsonEncoder implement Encoder to write individual resources.
+// Interface implementation assertions.
 var _ Encoder = &yamlEncoder{}
 var _ Encoder = &jsonEncoder{}
-
-// seqEncoder implements SequentialEncoder to write resources in order.
-var _ OrderedEncoder = &seqEncoder{}
+var _ OrderedEncoder = &orderedEncoder{}
 
 // StringSlice represents zero or more flag values.
 type StringSlice []string
@@ -42,13 +40,22 @@ func (i *StringSlice) Set(value string) error {
 	return nil
 }
 
-// TagMap represents a map of key values for CUE TagMap for flag parsing.
-type TagMap map[string]string
+// TagMap represents a map of key values for CUE TagMap for flag parsing.  The
+// values are pointers to disambiguate between the case where a tag is a boolean
+// ("--inject foo") and the case where a tag has a string zero value ("--inject
+// foo=").  Refer to the Tags field of [cue/load.Config]
+//
+// [cue/load.Config]: https://pkg.go.dev/cuelang.org/go@v0.10.1/cue/load#Config
+type TagMap map[string]*string
 
 func (t TagMap) Tags() []string {
 	parts := make([]string, 0, len(t))
-	for k, v := range t {
-		parts = append(parts, fmt.Sprintf("%s=%s", k, v))
+	for tag, val := range t {
+		if val == nil {
+			parts = append(parts, tag)
+		} else {
+			parts = append(parts, fmt.Sprintf("%s=%s", tag, *val))
+		}
 	}
 	return parts
 }
@@ -62,10 +69,14 @@ func (t TagMap) String() string {
 // is not supported.
 func (t TagMap) Set(value string) error {
 	parts := strings.SplitN(value, "=", 2)
-	if len(parts) != 2 {
+	switch len(parts) {
+	case 1:
+		t[parts[0]] = nil
+	case 2:
+		t[parts[0]] = &parts[1]
+	default:
 		return errors.Format("invalid format, must be tag=value")
 	}
-	t[parts[0]] = parts[1]
 	return nil
 }
 
@@ -183,7 +194,7 @@ func NewSequentialEncoder(format string, w io.Writer) (OrderedEncoder, error) {
 	if err != nil {
 		return nil, err
 	}
-	seqEnc := &seqEncoder{
+	seqEnc := &orderedEncoder{
 		Encoder: enc,
 		buf:     make(map[int]any),
 	}
@@ -251,17 +262,25 @@ func IsSelected(labels Labels, selectors ...Selector) bool {
 	return true
 }
 
-type seqEncoder struct {
+type orderedEncoder struct {
 	Encoder
 	mu   sync.Mutex
 	buf  map[int]any
 	next int
 }
 
-func (s *seqEncoder) Encode(idx int, v any) error {
+// Encode encodes v in sequential or starting with idx 0.
+//
+// It is an error to provide idx values less than the next to encode.  Is is an
+// error to provide the same idx value more than once.
+func (s *orderedEncoder) Encode(idx int, v any) error {
 	s.mu.Lock()
 	defer s.mu.Unlock()
 
+	if idx < s.next {
+		return fmt.Errorf("could not encode idx %d: must be greater than or equal to next idx %d", idx, s.next)
+	}
+
 	// If this is the next expected index, encode it and any buffered values
 	if idx == s.next {
 		if err := s.Encoder.Encode(v); err != nil {
@@ -284,6 +303,10 @@ func (s *seqEncoder) Encode(idx int, v any) error {
 		return nil
 	}
 
+	if _, ok := s.buf[idx]; ok {
+		return fmt.Errorf("could not encode idx %d: already exists", idx)
+	}
+
 	// Buffer out-of-order value
 	s.buf[idx] = v
 	return nil
@@ -297,6 +320,7 @@ type BuildOpts struct {
 	Stderr      io.Writer
 	WriteTo     string
 	Path        string
+	Tags        []string
 }
 
 func NewBuildOpts(path string) BuildOpts {
@@ -306,5 +330,6 @@ func NewBuildOpts(path string) BuildOpts {
 		Stderr:      os.Stderr,
 		WriteTo:     "deploy",
 		Path:        path,
+		Tags:        make([]string, 0, 10),
 	}
 }

internal/util/run.go

@@ -43,10 +43,11 @@ func RunCmd(ctx context.Context, name string, args ...string) (result RunResult,
 	cmd.Stdout = result.Stdout
 	cmd.Stderr = result.Stderr
 	log := logger.FromContext(ctx)
-	log.DebugContext(ctx, "running: "+name, "name", name, "args", args)
+	command := fmt.Sprintf("%s '%s'", name, strings.Join(args, "' '"))
+	log.DebugContext(ctx, "running command: "+command, "name", name, "args", args)
 	err = cmd.Run()
 	if err != nil {
-		err = fmt.Errorf("could not run command: %s %s: %w", name, strings.Join(args, " "), err)
+		err = fmt.Errorf("could not run command:\n\t%s\n\t%w", command, err)
 	}
 	return result, err
 }
@@ -55,15 +56,25 @@ func RunCmd(ctx context.Context, name string, args ...string) (result RunResult,
 func RunCmdW(ctx context.Context, w io.Writer, name string, args ...string) (result RunResult, err error) {
 	result, err = RunCmd(ctx, name, args...)
 	if err != nil {
-		err = fmt.Errorf("could not run command: %s %s: %w", name, strings.Join(args, " "), err)
 		mu.Lock()
+		defer mu.Unlock()
 		_, err2 := io.Copy(w, result.Stderr)
-		mu.Unlock()
 		if err2 != nil {
 			err = fmt.Errorf("could not copy stderr: %s: %w", err2.Error(), err)
 		}
 	}
-	return
+	return result, err
+}
+
+// RunCmdA calls RunCmd and always copies the result stderr to w.
+func RunCmdA(ctx context.Context, w io.Writer, name string, args ...string) (result RunResult, err error) {
+	result, err = RunCmd(ctx, name, args...)
+	mu.Lock()
+	defer mu.Unlock()
+	if _, err2 := io.Copy(w, result.Stderr); err2 != nil {
+		err = fmt.Errorf("could not copy stderr: %s: %w", err2.Error(), err)
+	}
+	return result, err
 }
 
 // RunInteractiveCmd runs a command within a context but allows the command to

version/embedded/minor

@@ -1 +1 @@
-100
+101

version/embedded/patch

@@ -1 +1 @@
-0
+2